General Reuse and Salvage Guideline for Hydraulic Piston Pumps and Motors {5058, 5070} Caterpillar


General Reuse and Salvage Guideline for Hydraulic Piston Pumps and Motors {5058, 5070}

Usage:

MT700 018
Agricultural Tractor
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Articulated Truck
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Asphalt Paver
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Backhoe Loader
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Challenger
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Combine
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Compact Track Loader
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Earthmoving Compactor
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Hydraulic Shovel
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Multi Terrain Loader
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Off-Highway Truck/Tractor
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Pipelayer
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Road Reclaimer/Soil Stabilizer
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Rock Feeder
RF300 (S/N: RF41-UP)
Rock Mover
RM900 (S/N: RF31-UP)
Rotary Drill
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Soil Compactor
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Track Feller Buncher
Blount Branded
Caterpillar
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Wheel Feller Buncher
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Wheel Loader
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Wheel Skidder
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Wheel Tractor-Scraper
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Wheeled Excavator
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Introduction

Table 1
Revision  Summary of Changes to SEBF9307 
23  Added new serial number prefixes 
22  Added new serial number prefixes 
21  Added new serial number prefixes. 
20  Update Effectivity 
19  Made correction to the caption in Illustration 242. Updated effectivity 

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat Dealersonly. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law. Information contained in this document is considered Caterpillar: Confidential Yellow.

This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For questions or additional information concerning this guideline, submit a form for feedback in the Service Information System. To address an urgent issue, use the following resources to communicate your request to Caterpillar Repair Process Engineering:

  • Caterpillar Dealer Technical Communicator

  • Dealer Solution Network

  • Caterpillar Technical Representative

  • Knowledge Network

Canceled Part Numbers and Replaced Part Numbers

This document may include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Summary

The purpose of this document is to give visual guidelines to see if piston pump and motor parts can be used again.

When used in the same application, parts that can be used again can be expected to give normal performance until the next overhaul.

Never install a part that this document shows cannot be used again.

During reconditioning, correct any conditions that might have caused the original failure.

Important Safety Information



Illustration 1g02139237

Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.

Improper operation, lubrication, maintenance, or repair of this product is dangerous. Improper methods could result in injury or death.

Do not operate or perform any lubrication, maintenance, or repair of this product, until you understand the operation, lubrication, maintenance, and repair information. Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.

Hazards are identified by a safety alert symbol. Safety alert symbols are followed by a signal word such as "Warning" that is shown below.



Illustration 2g02662636

The following is the meaning of the above safety alert symbol:

  • Pay Attention!

  • Become Alert!

  • Your Safety is Involved.

The message that appears under the warning explains the hazard. The message will be written or pictorially shown.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and on the product are not all inclusive. If a tool, a procedure, a work method, or an operating technique that is not recommended by Caterpillar is used, ensure that the procedure is safe for all personnel around the machine. Also ensure that the product will not be damaged or be made unsafe by the operation, lubrication, maintenance, or repair procedures.

All of the information, specifications, and illustrations that are in this publication are based on information that was available at the time of publication. The following information could change at any time: specifications, torque, pressures, measurements, adjustments, illustrations and other items. These changes can affect the service that is given to the product. Obtain the most current and complete information before you start any job. Caterpillar dealers have the most current information that is available.

Safety

------ WARNING! ------

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the steering system.


------ WARNING! ------

Personal injury can result from hydraulic oil pressure and hot oil.

Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.



NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.

Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.

Dispose of all fluids according to local regulations and mandates.


References

Table 2
References 
Media Number  Title 
PECJ0003  "Cat Hand Tools and Shop Supplies" 
PEGJ0075  "Cat Loctite Global Crossover List" 
SEBF9236  "Fundamentals of High Velocity Oxygen Fuel (HVOF) Spray for Reconditioning Components" 
SEBF9238  "Fundamentals of Arc Spray for Reconditioning Components" 
SEBF9240  "Fundamentals of Flame Spray for Reconditioning Components" 
NENG2500  "Dealer Service Tool Catalog" 

Tooling and Equipment

Table 3
Required Tools 
Part number  Part Description 
7B-0337  Surface Plate 
NA  Optical Flat 
NA  V-Block 
8T-5096  Dial Indicator Gp 
4C-8648  Cleaner (Hydrosolv 4110) 
Loctite 242  Threadlocker 

Table 4
Optional Tools 
Source  Description 
Lapmaster International (lapmaster.com)  Lapping Machine 
Sunnen (sunnen.com)  Convex Barrel Lap Machine 

Cleaning Procedure

Before a part is inspected, wash the part in a clean solvent made from petroleum. Wash each part separately. If several parts are washed together, there is a possibility that the machined surface can be damaged. Use compressed air to dry the part. Put hydraulic oil on the part to prevent rust or corrosion. Put the part in a clean container. Use a lint-free towel to clean the part before assembly. Be sure to put oil on all of the parts during assembly.

Inspection Procedure

Piston pump and motor parts have wear patterns that can be seen but not felt by a fingernail or pencil lead after salvage procedure. This type of wear has no effect on the performance of the part. Unless stated in this guideline, parts cannot be used again that have wear patterns felt with a fingernail or pencil lead after the salvage procedure. Throughout this guideline, the fingernail or pencil lead inspection will be used to determine if a part can be used again.

Touch Lapping Procedure

The touch lapping procedure is used on some parts to salvage that part. The touch lapping procedure will not give a part a “like new” surface or surface flatness. The procedure is used only to remove discoloration and small surface marks.

Use 4/0 emery polishing paper. Refer to Tool Catalog, PECJ0003, "Cat Hand Tools and Shop Supplies". Put the emery paper on a ground surface plate ( 7B-0337 Plate) so the paper is smooth. Do not use any other surfaces.

Wash the part in a clean solvent. Let the part dry at room temperature. Put hydraulic oil on the part and then put the part in a clean container.

  1. Wet the emery paper with a clean solvent made of a petroleum base.

  2. Place the part on the emery paper with the surface to be "touch lapped" on the paper.


    Illustration 3g02552199
    Touch lapping procedure used on a piston slipper face.

  3. Move the part in a pattern tracing out a number "8". More than ten complete number "8" patterns is not necessary. Refer to Illustration 3.

  4. Wash the part in a clean solvent. Let the part dry at room temperature.

  5. Put hydraulic oil on the part, and then put the part into a clean container.


NOTICE

When you handle or put pump and motor parts in storage, care must be taken to prevent damage to the machined surfaces.


Hand Lapping Procedure For Concave Barrels

Some barrel assemblies with bronze, concave seal faces can have discoloration or light scratches. These assemblies can be salvaged by hand lapping. Hand lapping does not give parts "like new" surfaces, but does create "near new" surfaces that allow the part to be used again.



Illustration 4g02552218
Apply compound at several points on sealing surface.

Use Grade A silicon carbide lapping compound that is suspended in a paste type lubricant. Clover Compound, Thixogenous-Greasemix, or an equivalent is recommended. Apply the compound to several locations on the surface that is to be lapped. Refer to Illustration 4.



Illustration 5g02552236

Place the port plate on top of the barrel assembly in an operating position. Apply firm pressure downward on the port plate while sliding plate back and forth in a circular motion. At the same time, rotate the barrel assembly. Refer to Illustration 5. After a brief time, the lapping compound will lose lubricity (lubrication capability) and become dry. At this time, apply more compound.

When the discoloration and light scratches are removed, thoroughly clean the components to remove lapping compound before using again. A clear solvent is recommended.



Illustration 6g02552237
Barrel and port plate after hand lapping.

Power Lapping Procedure

Power lapping can remove wear patterns and surface scratches, providing a "near new" surface flatness on parts. The power lapping machine can be used on a wide range of parts that require flat, smooth surfaces. Power lapping can produce lap flat surfaces within tolerances of one light band ( 2.95 µm (116 microinch)). Consistent surface finishes of 2 to 3 RMS with absolute uniformity are easily attained.

Lapping machines are easy to operate. However, some general guidelines must be followed.

  1. Check the lapping plates periodically, preferably every morning before starting production, to ensure lap plate flatness.

  2. Fill the slurry tank with a lapping vehicle. The vehicle is purchased premixed, and a lapping compound should be added to the vehicle at a rate of 8 oz. per gallon.

  3. Run the machine without parts for 4 to 6 minutes allowing the compound to mix evenly in the vehicle.

  4. Load the parts to be lapped inside the conditioning rings. The parts should be free to move about within the ring and not packed remaining stationary.

  5. Lapping times will vary according to the severity of the flaw that is to be removed. Minor scratches or warpage can usually be removed within 30 to 60 minutes.

  6. Before inspecting the flatness of the lapped part:

    1. Remove the dull finish caused by the lapping compound.

    2. Wash the part thoroughly.

    3. Polish the lapped surface, using 600 grit emery paper on a 4/0 polishing stand, until surface reflects light.

Testing For Flatness



Illustration 7g02552240
Optical flat.

A monochromatic light source and an optical flat are required to determine flatness. Refer to Illustration 7.



Illustration 8g02552242
Light band pattern.

Test for flatness by observing the light, emitted from the monochromatic light head, reflecting from the surface being checked, up through the optical flat. A series of dark bands and light spaces will be projected. Refer to Illustration 8. The dark bands are not light rays, but show where interference is produced by reflections from the test piece in the optical flat. Inspect the light bands for straightness. If the bands are straight and parallel, the surface is flat. If the bands are curved, the surface is not flat but may be flat enough for your particular needs.

Variable Pump Rotating Group

Nomenclature



Illustration 9g03349220
(1) Piston Actuator
(2) Retraction Plate
(3) Swashplate
(4) Outboard Shaft Bearing
(5) Drive Shaft
(6) Piston and Slipper Assembly
(7) Barrel Assembly
(8) Inboard Shaft Bearing
(9) Rod Actuator
(10) Port Plate

Rotating Group on Bent Axis Pumps/Motors



Illustration 10g03349242
(1) Piston Shaft
(2) Barrel Assembly
(3) Piston Shaft Assembly
(4) Piston Retainer
(5) Link-Type Piston Assembly


Illustration 11g03351822

Class sizes of piston sets are identified by the marks engraved on top. Example shown in Illustration 11 is class size II. Refer to Special Instruction, SEBF8113, "Specifications for L-Series Reusable Hydraulic Pump and Motor Components".



Illustration 12g03351829

Pintle shaft is matched to a specific piston drive shaft and must not be interchanged with other piston shafts. Refer to Illustration 12.



Illustration 13g03351836

Spherical ball is ground to match a specific shaft assembly and cannot be interchanged. Refer to Illustration 13.

Working Piston Assembly and Center Pin

Piston Slipper

Check to see if the slipper will move by hand on the piston ball. The slipper can feel loose or tight but must move in all directions without binding. If binding is felt, do not use the piston assembly again.

Note: Be sure that the lubrication port is not plugged. Use a wire to check the hole.



Illustration 14g03398342
Piston slipper with shallow grooves on the side of slipper.
Use Again

Slipper Face Nomenclature



Illustration 15g03398371
(1) Bearing Area
(2) Lubrication Port
(3) Balance Land
(4) Piston

Note: Polishing marks on the new faces are normal. These marks cannot be felt with a fingernail or pencil lead.

Slipper Face

Check to see if the slipper will move by hand on the piston ball. The slipper can feel loose or tight but must move in all directions without binding. If binding is felt, do not use the piston assembly again.

Note: Be sure that the lubrication port in not plugged. Use a wire to check the hole. Refer to Illustration 15.



Illustration 16g03351926
Piston assembly with scratches to bearing surfaces. Use the "Touch Lapping Procedure"
Use Again - Only if reuse criteria are met.


Illustration 17g02639836
Piston assembly after touch lapping procedure. Not all scratches and erosion were removed.
Do Not Use Again


Illustration 18g03354568
Piston assembly with large "pop outs" and metal embedded in bearing area.
Do Not Use Again


Illustration 19g03354582
Slipper with smeared face.
Do Not Use Again


Illustration 20g02653537
Piston assembly with foreign material in the slipper face.
Do Not Use Again


Illustration 21g03398441
Piston assembly with discoloration on the slipper face. Use the touch lapping process.
Use Again


Illustration 22g02640056
No discoloration can be seen on the balance land or bearing area after touch lapping procedure.
Use Again


Illustration 23g03398617
Piston assembly with fine scratches on the slipper face. Use the touch lapping procedure.
Use Again


Illustration 24g03398619
Piston assembly after touch lapping procedure. Scratches on the balance land cannot be felt with fingernail or lead pencil.
Use Again


Illustration 25g03398621
Piston assembly with grooves that are not deep on the side of the slipper.
Use Again


Illustration 26g02505556
Piston slipper severely damaged due to cavitation and contamination.
Do Not Use Again


Illustration 27g02653656
Slipper face with erosion in the balance land.
Do Not Use Again


Illustration 28g02653699
Slipper face with rolled edge.
Do Not Use Again

Note: The corners of the piston slippers must be square.



Illustration 29g02653777
Corners of piston slippers must be square.


Illustration 30g02653838
Slipper feet should freely rotate.

Piston Slipper Thickness



Illustration 31g02640796
Measurement of the slipper foot thickness.

Note: The slipper foot thickness of all the pistons from a single pump or motor must be measured.

No pits, scratches, nicks, or indentations are allowed which extend across more than 50% of the width of the sealing land surfaces. "Above the surface" irregularities are not allowed. Rework by touch or power lapping.

Piston Assembly End Play



Illustration 32g02641697


Illustration 33g03125140

Check the end play of the piston assembly with a V-block, two other pistons, a dial indicator and a flat plate. Put the piston to be measured in the V of the V-block on the slipper back faces. Put the dial indicator into position with the pointer on the end of the piston. Refer to Illustration 32. Push down on the piston and set the dial indicator at zero. Pull up on the piston. Refer to Illustration 33. If the dimension measured is more than the piston assembly end play allowance, the piston assembly cannot be used again.

Piston and Piston Rings



Illustration 34g02713192
(1) Piston Ball
(2) Piston Shaft
(3) Ring grooves for piston rings

Groove or seizure marks on piston ball or piston shaft are not acceptable. If this damage is present, the parts must be replaced. Breakouts or other damage to ring groove are not allowed.

Seizure marks on the piston ball are indications of dirt. Seizure marks on the piston shaft are indications of exceeding the permissible maximum speed of the motor. If grooves can be felt, the hydraulic fluid may be contaminated. Dull contact points are acceptable.



Illustration 35g03351940
Ball head with scratches that cannot be felt with a pencil lead or fingernail.
Use Again


Illustration 36g02714077
Pistons with slight wear on tapered shaft that cannot be felt with a pencil lead or fingernail.
Use Again


Illustration 37g03351942
Piston rings with slight wear that cannot be felt with a pencil lead or fingernail.
Use Again


Illustration 38g03351944
Wear on piston rings (sealing surface) that can be felt with a pencil lead or fingernail.
Do Not Use Again


Illustration 39g03351947
Broken piston ring.
Do Not Use Again


Illustration 40g03289176
Clearance between the piston rings and the piston grooves.

Clearance, measured with a feeler gauge, should not exceed 0.10 mm (0.004 inch). The piston rings, and possibly the piston, must be replaced if clearance is exceeded.

Wear on the thickness of the piston rings is a result of fine contamination in the hydraulic fluid. In addition to wear on the piston ring, wave-shaped marks can normally be found on the control surface of the control lens.



Illustration 41g03351948
Pistons with scratches that can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 42g03351950
Piston with metal flakes or scratches that can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 43g03355671
Piston assembly with blue discoloration on the piston.
Do Not Use Again


Illustration 44g03355672
Piston assembly with gray bands on the piston.
Use Again


Illustration 45g03351952
Piston assembly with discoloration and scratches that cannot be felt with fingernail or lead pencil.
Use Again


Illustration 46g03351954
Piston exposed to severe contamination.
Do Not Use Again


Illustration 47g03355704
Arrow points to a phenolic filler that is loose and chipped around the edge.
Do Not Use Again


Illustration 48g03355713
An arrow points to a phenolic filler that is loose or protrudes from barrel of piston.
Do Not Use Again


Illustration 49g02664358
Piston filler has erosion.
Do Not Use Again


Illustration 50g03356371
Piston that has lost the slipper.
Do Not Use Again

Center Pin



Illustration 51g02713158
(1) Spring plate impression on the bottom of the center pin
(2) Ball head
(3) Center pin shaft

Center pin should have no grooves or traces of seizure on the ball head. Small or light grooves on the circumference of center pin shaft are acceptable.

A spring plate impression does not require replacement of the center pin. However, the impression indicates:

  • Separation (lift-off) of the barrel from the port plate. Separation can result from insufficient oil supply (cavitation) in reverse mode.

  • Seizure on the ball head because of the end play.

  • The rotary group was not pulled back against the retaining ring after inserting into the housing.

  • When fitting the motor to the gear box, the drive shaft was pushed in, thus using up all of the end-play.


Illustration 52g02713176
Center pin with scratches on the ball head that cannot be felt with a pencil lead. No grooves, no traces of seizure.
Use Again


Illustration 53g03356375
Left side of Illustration shows center pin with worn ball head. Right side shows center pin with seized ball head.
Do Not Use Again

Cup Springs



Illustration 54g02713288
Replace cup springs if wear can be seen. Wear is indicated by polished areas.


Illustration 55g02713300
Assemble springs as shown.

Piston Shoe Retainer



Illustration 56g02545463
No evidence of abrasion and scratching on mating surface for ball retainer.
Use Again

Ball Retainer

A retainer with an edge that can be felt with a fingernail or pencil lead where the contact area ends cannot be used again.



Illustration 57g02664637
Retainer with normal wear and cannot be felt with fingernail or pencil lead.
Use Again


Illustration 58g03351956
Retainer with extreme wear.
Do Not Use Again

Retainers must be free of nicks and scratches on the spherical face. Discoloration or blemishes that cannot be felt with a fingernail or pencil lead are permitted.



Illustration 59g02802556
Blemishes indicated by arrow which can be seen but not felt.
Use Again


Illustration 60g03355718
Splines extend three-quarters of the over-all height of the retainer. Retainer meets the reusability specifications.
Use Again


Illustration 61g03355726
Retainer chamfer matches the chamfer on the cylinder hub. Retainer meets the reusability specifications.
Use Again

Shoe Retainer and Ball Retainer



Illustration 62g03356381
Marks can be seen but not felt with fingernail or pencil lead.
Use Again


Illustration 63g02545536
Lapping the shoe retainer to the ball retainer.

To improve the mating surface between the shoe and ball retainers:

  • Apply lapping compound to the ball retainer.

  • Apply pressure to the shoe retainer.

  • Rock in all directions.

Seal Retainer



Illustration 64g03355745
Markings that can be seen but not felt with a fingernail or pencil lead are acceptable.
Use Again

Wear Plate



Illustration 65g02645623
Wear plate with groove and wear step in the slipper seal area.
Do Not Use Again


Illustration 66g03351964
Wear plate with heat cracks that can be felt with a fingernail or lead pencil.
Do Not Use Again


Illustration 67g03355754
Wear plate with a scratch across the slipper seat area that can be felt with a fingernail or lead pencil. Wear plates should not be used again without first power lapping to remove scratches.
Use Again - After Power Lapping.


Illustration 68g03351967
Wear plate with smeared surface and corrosion pitting.
Do Not Use Again


Illustration 69g03351972
Damage caused by piston that has lost a slipper.
Do Not Use Again


Illustration 70g03352244
Wear plate that is polished in the slipper seat area.
Use Again


Illustration 71g03352247
Wear plate with scratches that cannot be felt with a fingernail or lead pencil.
Use Again


Illustration 72g03352250
Wear plate with discoloration on the back side.
Use Again


Illustration 73g03352252
Wear plate with circumferential marks on the back side.
Use Again

Retraction Bearing



Illustration 74g03356387
Retraction bearing with normal wear on slipper surface that cannot be felt with a fingernail or lead pencil. Use the touch lapping procedure on the bearing before installation.
Use Again


Illustration 75g03356393
Retraction bearing with high spots that cannot be felt with a fingernail or lead pencil. Use the touch lapping procedure on the bearing before installation.
Use Again

Retraction Plate



Illustration 76g02645578

Make sure that the retraction plate is flat. Put the retraction plate on a surface plate. With fingers and thumb, push down on opposite edges and see if any rocking motion can be felt. If rocking motion can be felt, the plate is not flat and cannot be used again unless made flat by power lapping.



Illustration 77g03352262
Retraction plate with wear at slipper contact area.
Use Again


Illustration 78g03352264
Retraction plate with wear on the outside diameter that can be felt with a fingernail or lead pencil may be salvaged by power lapping.
Use Again - After touch lapping, if plate is flat.


Illustration 79g02552378
Retraction plate.
Use Again - After touch lapping, if plate is flat.


Illustration 80g03352270
This plate shows damage from slipper "lifting". Polished or scored surfaces on the area where the spherical washer rides is not acceptable.
Do Not Use Again

Port Plate

Port Plate Nomenclature and Issues



Illustration 81g02711304
(1) Control Surface
(2) Contact Surface between port plate and barrel.

If there is wave-shaped wear on the control surface of the control plate, then the control surface must be replaced. This wear can be felt with a pencil between the kidney shaped slots.

Wave-shaped run-in is a result of fine dirt particles in the pressure fluid. A high density of solid matter particles ranging from 5 to 10 microns has the effect of lapping paste.

If both the port plate and barrel are to be replaced with new parts, then no lapping is necessary. New parts are ground to dimension and are interchangeable. When new and used parts are paired, the control surface must be lapped together.



Illustration 82g03349254
(3) Rib
(4) Seal Bands
(5) Thrust Face
(6) Port


Illustration 83g02711370
Contact surface of the port plate must be flat and level. Inspect the levelness with a straight scale.
Use Again

Note: Use the power lapping procedure on both sides of all port plates that can be used again before plates are installed.

A port plate that has scratches or scored marks that can be felt with a fingernail or pencil lead on the critical surfaces or between the ports cannot be used again. Port plates that are smeared or galled on the critical surfaces or have blue discoloration cannot be used again. An indication of a smeared or galled port plate is bronze colored material on the port plate surface.

Use the touch lapping procedure on port plates that have scratches or score marks that can be seen but cannot be felt.

Note: If a port plate and a bearing plate are exchanged at the same time, then lapping is not necessary. New spare parts are ground to dimension at the factory and are interchangeable. When matching used parts with new parts, lapping is required.



Illustration 84g03352273
Port plate that has erosion in the seal band.
Use Again - After power lapping.


Illustration 85g02645858
Port plate after the power lapping procedure.
Use Again


Illustration 86g02646097
If power lapping removes scratches between ports and in the seal band.
Use Again


Illustration 87g03352275
Port plate with scratches in the seal band and thrust surface that cannot be felt with a fingernail or lead pencil.
Use Again


Illustration 88g02646189
Port plate with a machine mark in the rib should not be used again without first power lapping.
Use Again - After power lapping.


Illustration 89g03356396
Port plate with smeared thrust face should not be used again without first power lapping.
Use Again - After power lapping.


Illustration 90g03356398
Port plate with discoloration should not be used again without first power lapping.
Use Again - After power lapping.


Illustration 91g03352278
This port plate has light burn marks and no heat checking. Should not be used again without first power lapping.
Use Again - After power lapping.


Illustration 92g03352279
Port plate with heavy burn marks and scoring.
Do Not Use Again


Illustration 93g03352282
Port plate with light scratches on seal band.
Use Again - After touch lapping.


Illustration 94g03355792
Port plate with scratches across the seal band that can be felt with a fingernail or lead pencil.
Do Not Use Again


Illustration 95g03352284
Port plate with discoloration.
Use Again


Illustration 96g03352291
Port plate with discoloration on the back side.
Use Again


Illustration 97g02670177
Port plate is etched in the port seal area.
Do Not Use Again


Illustration 98g03356400
After touch lapping procedure, port plate was not possible to remove all the discoloration from the critical surfaces on the port plate.
Do Not Use Again


Illustration 99g02670399
Port plate with cavitation erosion in the port area.
Do Not Use Again


Illustration 100g03352334
Port plate with pitting in seal band.
Use Again - After power lapping procedure and reuse criteria are met.


Illustration 101g03352337
Port plate with light pitting.
Use Again - After power lapping and reuse criteria are met.

Visually inspect for cracks at the drive slot and kidneys (port openings).

Note: Penetrant inspection may be necessary to detect cracks.

On all bi-metal bearing plates, in addition to a visual inspection, use penetrant inspection to detect cracks on the bronze surface of the plate.

Note: No steel may be visible through the bronze surface of bimetal port plates.

No pits, scratches, nicks, or indentations are allowed which extend across more than 50% of the width of the sealing land surfaces. "Above the surface" irregularities are not allowed. Rework by touch or power lapping.



Illustration 102g02670556
Location of sealing land surfaces on both sides of port plate (Typical).

Use a magnetic particle inspection procedure to detect cracks. Cracks are not allowed on any surface of the part.

Use a new port plate for field repair if the above inspection procedures cannot be exercised. This procedure is to ensure that the port plate is not cracked or softened.

Scrap valve plates that show smearing or metal transfer on the running surface of the mating bearing plate (barrel assembly surface if a separate port plate is not used.)

For medium-duty valve plates, use a penetrant inspection to detect cracks on the bronze surface of the part.

Barrel Assembly

Nomenclature and Issues



Illustration 103g03352341
(1) Seal bands
(2) Port
(3) Splines
(4) Bronze surface / Thrust surface


Illustration 104g02646441
Barrel assembly with wear step in the seal band can be used again if wear step can be removed by power lapping salvage procedure.
Use Again - After power lapping.


Illustration 105g03352351
Barrel assembly with corrosion and scratches across the seal band that cannot be removed by use of the power lapping procedure.
Do Not Use Again


Illustration 106g02646457
Barrel assembly with polished surface and no wear step in the seal band and thrust surface.
Use Again


Illustration 107g03356403
Barrel assembly with discoloration. Scratches in the block surface cannot be felt with a fingernail or lead pencil.
Use Again


Illustration 108g03352353
Barrel assembly with heat cracks in the thrust surface.
Do Not Use Again


Illustration 109g03352362
Barrel assembly with smeared thrust surface. Use the touch or power lapping procedure.
Use Again - After lapping.


Illustration 110g03352364
Barrel assembly with damage between ports.
Do Not Use Again


Illustration 111g03352366
Barrel assembly with erosion at the ports on concave bronze face.
Use Again - After hand lapping if reuse criteria are met.


Illustration 112g03356406
Barrel assembly with smearing on bronze face.
Use Again - After hand lapping reuse criteria are met.


Illustration 113g03356408
Barrel assembly with scoring on bronze face.
Use Again - After hand lapping if reuse criteria is met.


Illustration 114g03352368
Barrel assembly with discoloration and light scratches on concave bronze face that can be felt with a fingernail or pencil.
Use Again - After hand lapping.


Illustration 115g03352372
Barrel assembly with deep scratches on concave bronze face that cannot be removed by hand lapping.
Do Not Use Again


Illustration 116g02710486
(5) Cylinder bores
(6) Control surface

Lapping the Barrel to the Port Plate

If the barrel and the port plate are both replaced at the same time, then lapping is not necessary. New parts are ground to dimension and are interchangeable. When matching used parts with new parts, lapping is required.

Abrasives


NOTICE

When using abrasives, limit exposure to skin to avoid irritation. Avoid inhalation if the abrasive is in the form of powder.


Silicon Carbide and Aluminum Oxide lapping compound are recommended for the abrasives. A medium-fine 500-600 grit (17-14 microns) Silicon Carbide is desired for pre-lapping. A medium-fine 500-600 grit (17-14 microns) Aluminum Oxide is desired for final lapping. Silicon Carbide will remove material from the port plate and Aluminum Oxide will help with achieving the desired surface finish. Lapping compound can be obtained in a paste or a powder. Lapping compound should be mixed with a light oil. Avoid water base compounds. When preparing the compound, obtain a syrup consistency. The mixture should contain 50% oil.

Surface Examination

The following steps will provide a method to check the barrel and the port plate.

  1. Examine the surface of the port plate and barrel. Look for wear if the components are used. Light scratches can be removed by lapping. Use a sharp pencil to identify any large grooves or imperfections. Parts may need replaced if a pencil cannot easily run over the grooves or imperfections.

  2. Examine the surface roughness of the barrel and port plate. An average roughness of 0.1 µm (3.9 microinches) is acceptable for the port plate. An average roughness of 0.2 - 0.3 µm (7.8 - 11.8 microinches) is acceptable for the barrel.


    Illustration 117g03177976


    Illustration 118g03177977

  3. Scribe at least three lines using pencil lead from the center of the barrel outward. This procedure will verify the mating of the two parts. See Illustrations 117 and 118.

  4. Center the port plate on the barrel. Rotate the port plate on the barrel. Apply light pressure and make five rotations.


    Illustration 119g03178002
    Unacceptable


    Illustration 120g01341586
    Acceptable

  5. Remove the port plate from the barrel. Check the pencil lead marks. Record the wear pattern. Examine the remaining length of the lead marks.

    Note: 1/3 of the line should remain visible. The line should be located near the center of the barrel. Illustration 119 indicates an unacceptable barrel. Illustration 120 indicates an acceptable barrel. Start the procedure if any one condition exists.

Initial lapping



    Illustration 121g01342951

  1. Apply a light coat of 500-600 grit (17-14 microns) Silicon Carbide lapping compound to the port plate. Place the barrel on the port plate. Refer to Illustration 121.


    Illustration 122g01342935


    Illustration 123g01342963

  2. Rotate the barrel in a circular motion while moving the barrel around the center of the port plate. The lapping motion should form an eccentric pattern. Refer to Illustrations 122 and 123. An eccentric pattern is desired so that grooves are not created from a repeated motion. Apply moderate pressure during lapping. Continue this process for 15 to 20 passes.

    Note: The large cross hair indicates the center of the port plate which lies below the barrel. The small cross hair indicates the center of the barrel on an eccentric path.

  3. Clean the barrel and the port plate with a solvent to remove the lapping compound. Repeat Steps 1 through 5 in the "Surface Examination" section. If the desired result is not achieved, continue lapping. Move to Step 4 once the surface is free from scratches and imperfections.

    Note: Step 4 uses the file method for testing hardness. This step is not to be confused with traditional Rockwell testing. Hardness testing files and instructions can be obtained from a local tool supplier.

  4. Perform a hardness test on the port plate using the file method. Use a hardness testing file at 65 Rockwell C. Check the lands that have been affected by lapping. The part must be replaced if the hardness file scratches the surface. Insome cases, the amount of material removed from the port plate may be too great to maintain the minimum material harness of 67 Rockwell C. Proceed to the final lapping procedure if the recommended results were achieved.

Final Lapping

  1. Apply a light coat of 500-600 grit (17-14 microns) Aluminum Oxide lapping compound to the port plate. Place the barrel on the port plate.

  2. Rotate the barrel in a circular motion while moving the barrel around the center of the port plate in an eccentric pattern. Refer to Illustrations 122 and 123. An eccentric pattern is desired so that grooves are not created from a repeated motion. Apply moderate pressure while lapping. Continue this process for 15 to 20 passes.

  3. Clean the barrel and port plate with a solvent to remove the lapping compound.

  4. Apply a light coat of oil to the port plate to prevent corrosion. Place the barrel on the port plate.


Illustration 124g03352406
Cylinder bores with scoring that can be seen. The barrel in the illustration was cut to show the scoring.
Do Not Use Again

Note: Cylinder bores cannot be reworked. Therefore, if there are scratches, grooves, scoring, local indentations, or break-out in the piston stroking area, further inspection is not needed. The barrel must be replaced. Refer to Illustration 124.



Illustration 125g03352885
Barrel assembly with broken piston and damaged piston sleeve.
Do Not Use Again


Illustration 126g03352888
Barrel assembly with damage to piston sleeve.
Do Not Use Again.


Illustration 127g03352889
Barrel assembly with heavy scoring on piston sleeve.
Do Not Use Again.


Illustration 128g03356410
Barrel assembly with no scoring on piston sleeve.
Use Again - After washing in clean solvent.


Illustration 129g03352925
Barrel with grooves in the control surface that cannot be removed by lapping the barrel to the port plate.
Do Not Use Again


Illustration 130g03352955
Breakouts in the area of the cylinder bores on the spherical control surface are likely caused by cavitation.
Do Not Use Again

Dark discoloration on the control surface is not a sign of damage. However, with pittings (lead washouts), dark discolorations are indications of overheating. Single pittings can be removed with lapping. Interlinked pittings or breakouts and/or cracks along the core borders require replacement of the barrel.



Illustration 131g03356413
Spherical control surface with a stepped outer border that can be felt with a pencil lead or fingernail.
Do Not Use Again

Barrel Assembly Bores and Piston Fit

Use the following procedure to check the barrel assembly bores.

  1. Wash the barrel assembly and piston in a clean solvent. Use compressed air to dry off the barrel assembly and piston.

  2. Put a piston into one of the bores to the maximum depth that the piston will go into the bore during operation.

  3. Feel for side movement of the piston in each bore.


Illustration 132g02505858
How to check the side movement of a piston in a barrel assembly bore.

If no movement or only little side movement can be felt in all of the bores, the barrel assembly can be used again. Refer to Illustration 132.

Note: Use a piston in a new barrel assembly to see how much side movement can be permitted. If necessary, use a dial bore gauge to measure the bore diameters.

Barrel Assembly Spline Measurement



Illustration 133g02646661
Measurement of the barrel assembly splines.


Illustration 134g02665038
Measurement of barrel splines between pins.

If no wear can be seen on the barrel assembly splines, the barrel assembly can be used again. If necessary, use two pins and an inside micrometer to measure the splines (X) as shown in Illustration 134. Put the pins 180° apart in the worn area of the splines. For barrel assemblies that have an odd number of spline teeth, put the pins in splines as near to 180° apart as possible. Use clay or masking tape to hold the pins in position. Refer to manufacturer specifications. Refer to Illustrations 133 and 134.

Control Lens



Illustration 135g03289137
Control lens nomenclature.
(A) Control surface
(B) Contact surface between control lens and barrel.

If there is a wave-shaped wear on the control surface of the control lens, then the lens must be replaced. This wear can be felt with a pencil lead between the kidney-shaped slots.

Wave-shaped run-in is a result of fine dirt particles in the pressure fluid. A high density of solid matter particles smaller than 5 to 10 microns has the same effect as lapping paste.

If both the control lens and barrel are to be replaced with new parts, then no lapping is necessary. New parts are ground to dimension and are interchangeable. When used and new parts are paired, the control surfaces must be hand-lapped together.



Illustration 136g03355802
Spherical control surface with deep grooves that cannot be removed by lapping with the cylinder barrel.
Do Not Use Again


Illustration 137g03355805
Wear marks with deposits from the regulator housing that can be felt with a lead pencil. Wear marks cannot be lapped out as the hardened layer would be removed.
Do Not Use Again


Illustration 138g03355814
Discoloration and contact traces that cannot be felt with pencil lead.
Use Again


Illustration 139g03355821
Discoloration on backside of lens but no wear traces that can be felt with a pencil lead.
Use Again

Miscellaneous

Drum Seal



Illustration 140g03352959
Markings which can be seen but not felt with a fingernail or pencil lead are acceptable.
Use Again


Illustration 141g02804597
Abrasion and scratching which can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 142g03355822
Damage which can be seen and felt.
Do Not Use Again

Side Block



Illustration 143g02804839
If markings can be seen but not felt with a fingernail or pencil lead.
Use Again

Head Assembly



Illustration 144g03356416
Aeration damage.
Use Again - After lapping.


Illustration 145g03352965
Erosion on face.
Use Again - After lapping.


Illustration 146g03352970
Fine scratches and corrosion.
Use Again - After lapping.

Note: The surfaces shown in Illustrations 144,145, and 146 can be lapped to a maximum of 0.38 mm (0.015 inch). Metering notches must be altered accordingly. The bearing must be removed and replaced.



Illustration 147g03352974
Extreme damage caused by foreign object passing through pump.
Do Not Use Again


Illustration 148g02804842
Head assembly that has a scratch that can be felt with fingernail or pencil lead may be used again after power lapping.
Use Again


Illustration 149g02646717
Head assembly with a scratch that is not across the seal band or gasket surface. Remove any burrs on the scratch with the touch lapping procedure.
Use Again


Illustration 150g03352977
Head assembly with discoloration and polishing on the seal band and thrust surface may be used again after power lapping.
Use Again


Illustration 151g03352980
Head assembly with wear pattern on the seal band and thrust surface may be used again after power lapping.
Use Again


Illustration 152g02552760
Head assembly with no fretting or scratches on contact area of port plate.
Use Again


Illustration 153g02552761
Port plate with no fretting or scratches on contact bearing area of head assembly.
Use Again

Bearing Ring



Illustration 154g02710419
Use Again - If the following criteria are met:
(1) The outside diameter is undamaged.
(2) The front side is smooth and undamaged.
(3) Bearing bore with no turning or run-in traces.

Slotted Round Nut



Illustration 155g02710433

If the bearing assembly is removed from the drive shaft, the nut must always be replaced. Replacing the nut is a safety precaution.

When the drive shaft is assembled, secure the nut on the drive shaft with Loctite. Prior to assembly, the part should be cleaned with 4C-8648 Cleaner (Hydrosolv 4110).

Once threads on the drive shaft are clean, coat the thread with Loctite primer. This primer will improve the holding capability of the Loctite. The primer also shortens the drying time of the Loctite to approximately 20 minutes.

Finally, coat the male threads of the drive shaft with Loctite 242. The Loctite 242 should be applied only to the area under the nut, not to the complete length of the thread.

Cover



Illustration 156g02709742
Nomenclature
(1) Contact surface of the retaining ring
(2) Shaft seal seat
(3) Insertion radius for the O-ring


Illustration 157g02709755
No Traces of wear on the front side surface of the retaining ring. Wear can be caused by bearing damage. Shaft seal seat (3) with no scratches or grooves. No damage on the insertion radius for the O-ring (2).
Use Again


Illustration 158g03356420
Use Again - If marks, scratches, and light rust can be removed from the outer face of the front cover.


Illustration 159g02806916
No damage to the counterbore side for the seal or the groove for the O-ring indicated by the arrows.
Use Again


Illustration 160g02646786
Cover has no wear caused by contact with the impeller.
Use Again

Impeller



Illustration 161g03356421
Impeller with few chips in the keyway and no damage on the fins.
Use Again

Oil Seal Case

Marks, scratches, and light rust which can be removed are allowable on the outer face of the oil seal case.



Illustration 162g02806939
Outer surface of oil seal case.
Use Again - After cleaning and conditioning.


Illustration 163g03355841
Inner surface of oil seal case.
Use Again

Piston Stops



Illustration 164g02653120
Piston stops with wear but no cracks. Install the piston stops to use the back sides.
Use Again

Swash Housing



Illustration 165g03352984
Swash with scored trunnion. See Illustration 166.
Do Not Use Again


Illustration 166g03352987
Enlarged view of swash with scored trunnion.
Do Not Use Again

Swashplate

Fixed Swashplates

Both the pump and motor swashplates have contact surfaces that operate against the piston slipper faces. A swashplate whose contact surfaces has scratches or scored marks that can be felt with a fingernail of pencil lead cannot be used again without power lapping. Use the touch lapping procedure on a swashplate whose contact surface has scratches or score marks that can be seen but cannot be felt.

A swashplate whose contact surface has been smeared or galled cannot be used again. An indication of a smeared or galled contact surface is bronze-colored material on the swashplate.



Illustration 167g03355869
Swashplate with light scratches.
Use Again - After power lapping if reuse criteria are met. Refer to "Hand Lapping Procedure For Concave Barrels" in this document.


Illustration 168g03355872
Swashplate with light rust and scratches that can be felt with a fingernail or pencil lead.
Use Again - After power lapping.


Illustration 169g03353197
Swashplate with damage to slipper contact area and pivot socket for lubrication rod.
Do Not Use Again


Illustration 170g02964917
Swashplate after reconditioning by power lapping.


Illustration 171g03353202
Swashplate with light scratches on bearing contact areas that cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 172g03353215
Swashplate with fretting on bearing contact surface that can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 173g03353237
Swashplate cradle with bronze bearings.
Use Again - If inspection reveals no heavy scratches or wear pattern on bronze surface.

Hanger



Illustration 174g03398642
Swashplate with discoloration and polishing on the wear plate surface.
Use Again


Illustration 175g02647270
Swashplate with buttons that are polished but with no deep grooves or scoring.
Use Again


Illustration 176g03355874
Grooving can be seen but not felt with a fingernail or pencil lead.
Use Again


Illustration 177g03355877
Hanger trunnion bearing with damage and abrasion markings. Heat cracks on the machined surface of the hanger.
Do Not Use Again

Check the hanger trunnion bearings for damage or abrasion markings. Replace the bearings if damage is present. Refer to the Service Manual for the assembly procedure and the correct orientation. Refer to Illustration 177.

Check the machined surface of the hanger for heat cracks that can be seen and felt with a fingernail or pencil lead. Replace the hanger if damage is present. Refer to Illustration 177.

Creep Plate



Illustration 178g02688396
After using touch lapping procedure, a motor creep plate with normal wear that cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 179g03355882
Motor creep plate with score marks that can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 180g03353254
Motor creep plate shows bronze-colored material on contact surface.
Do Not Use Again

Swash Plate Assembly



Illustration 181g03353261
Swashplate assembly with pin bore that is elongated.
Do Not Use Again
Use a magnetic particle inspection procedure to detect cracks. Cracks are not allowed on any surface of the part.

Head



Illustration 182g03353272
Head with erosion on seal band surfaces.
Use Again - After power lapping.


Illustration 183g02965199
Head after reconditioning by power lapping.

Head Assembly with Port Plate



Illustration 184g02552760
Head assembly with no fretting or scratches on contact area of port plate.
Use Again


Illustration 185g02552761
Port plate with no fretting or scratches on contact bearing area of head assembly.
Use Again

Control Head



Illustration 186g03353297
Control head with smooth bushing bore.
Use Again


Illustration 187g03355885
Control head with damaged bushing bore area.
Do Not Use Again


Illustration 188g03353362
Control head with erosion on contact area of port plate.
Use Again - After power lapping.


Illustration 189g02967463
Control head after power lapping.

Housing



Illustration 190g02691118
Housing with no indication of turning or run-in traces in bearing seat. No scratches or grooves.
Use Again


Illustration 191g02647281
Housing with no scratches or grooves on the gasket surface.
Use Again


Illustration 192g02647288
Housing with no scratches or grooves in the seal counterbore. Arrow shows seal counterbore.
Use Again


Illustration 193g03353375
Housing with damaged control plate stop but no cracks. Install a new stop.
Use Again


Illustration 194g03355889
Control stop with normal wear on the contact surface.
Use Again


Illustration 195g03353405
Clean all surfaces of the mounting face.
Use Again


Illustration 196g03353407
Clean all port faces.
Use Again

All mounting faces including the inlet and outlet port face must be reconditioned to remove all rust and discoloration. No scratches which can be felt with a pencil lead or fingernail are allowed on the O-ring surface of the inlet and outlet ports. Refer to Illustrations 196 and 197.



Illustration 197g02557006
Casing after cleaning with no scratches.
Use Again

Valve Cover

Plate Side



Illustration 198g03355902
Mounting face needs reconditioned to remove rust and discoloration.
Use Again


Illustration 199g02556896
Valve cover after cleaning.
Use Again

Hose Connection Side

The inlet and outlet port faces must be reconditioned to remove all rust and discoloration. No scratches which can be felt with a pencil lead or fingernail are allowed on the O-ring surface of the inlet and outlet ports.



Illustration 200g03353414
Valve cover before cleaning that needs rust and discoloration removed.
Use Again


Illustration 201g02557000
Valve cover after cleaning.
Use Again

End Cover



Illustration 202g02691559
(1) Indexing pin for the end cover
(2) Contact surface of the end cover
(3) Port surfaces
(4) Threaded holes

Check End Cover for flatness.



Illustration 203g02691679
Surface of the end cover with no scratches or grooves, smooth, and level. Threaded holes are not damaged. Removal of fretting or corrosion can be done by lapping.
Use Again

Bearings


NOTICE

Bearings must always be replaced if removed from the shaft.




Illustration 204g02557016

Replace all bearings during rebuild.

Determine the reusability of the bearing before disassembly. No seizure, depression, or abnormal abrasion is allowed. The bearing must not be removed from the shaft if the bearing is reusable. If the bearing is removed, a new bearing must be installed. The press fit of the inner race on the shaft is critical.



Illustration 205g02557036
Bearing
Use Again - Only after preforming inspection and the bearing was not removed.

Piston

Negative Flow Piston


NOTICE

Do not attempt to remove scratches by polishing and reusing this part.




Illustration 206g03356113
Marks can be seen but not felt with a fingernail or pencil lead.
Use Again

Pilot Piston



Illustration 207g02807141
Wear on the surface of pilot piston has been proven to have adverse reaction characteristics with the high-pressure cutoff valve.
Do Not Use Again

Servo Sleeve



Illustration 208g03356117
Servo sleeve with normal wear in the bore that cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 209g03356120
Servo sleeve with scored bore that can be felt with a fingernail or pencil lead.
Do Not Use Again

Servo Piston



Illustration 210g02690660
Servo piston with normal wear that cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 211g03353422
Servo piston with normal wear that can be felt with a fingernail or pencil lead.
Do Not Use Again

Actuator Piston



Illustration 212g02552858
Actuator piston.
Use Again - If ring is not scored.


Illustration 213g03353433
Actuator piston rod.
Do Not Use Again - If ball socket is damaged.


Illustration 214g03353442
Actuator piston assembly.
Use Again - If scratches cannot be felt with fingernail or pencil lead and swage around ball is not damaged.


Illustration 215g03353449
Actuator piston assembly with scratches that cannot be felt with fingernail or pencil lead.
Use Again


Illustration 216g03354004
Actuator piston with damage to seal ring.
Use Again - After replacing seal ring.


Illustration 217g02552870
Actuator piston with no damage to seal or ball.
Use Again


Illustration 218g03356122
Actuator piston bearing with wear grooves.
Do Not Use Again - Replace bearing.


Illustration 219g02552876
Actuator piston cylinder.
Use Again - If actuator piston cylinder has no scratches that can be felt with fingernail or pencil lead.


Illustration 220g03354009
Actuator piston cylinder with wear grooves.
Do Not Use Again

Servo Piston Links



Illustration 221g03356124
Link with wear on the ball end that can be felt with a fingernail or pencil lead.
Do Not Use Again


Illustration 222g03354015
Link with polishing on the ball end that cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 223g03354020
Link with discoloration on the ball end that cannot be felt with a fingernail or pencil lead.
Use Again

Servo Inserts



Illustration 224g03354040
Insert with discoloration and no wear step.
Use Again


Illustration 225g02648048
Insert with wear on the bottom of the cup that cannot be felt with a fingernail or pencil lead.
Use Again

Large Piston



Illustration 226g03354044
Piston with light scratches that cannot be felt with a fingernail or lead pencil. Also, the piston moves smoothly in the bore.
Use Again


Illustration 227g03356129
Slight discoloration on the large diameter which cannot be felt with a fingernail or pencil lead is permitted.
Use Again


Illustration 228g03354045
Piston with scoring that can be felt with a fingernail or pencil lead.
Do Not Use Again

Link-Type Piston



Illustration 229g02965496
Link-type piston with no noticeable excessive wear
Use Again


Illustration 230g03354051
Link-type piston with fretting on top edge and wear marks on side.
Do Not Use Again

Cartridge



Illustration 231g03354062
Cartridge with scoring in the bore that can be felt with a fingernail or a pencil lead. Cartridge was cut to show the scoring.
Do Not Use Again


Illustration 232g03356133
Cartridge with wear caused by seals that cannot be felt with a fingernail or pencil lead.
Use Again

Sleeve



Illustration 233g03356136
Do Not Use Again - If scratches can be felt with a fingernail or pencil lead.


Illustration 234g03354066
Sleeve with scoring that can be felt with a fingernail or pencil lead but no deep grooves on the lands. Also, the sleeve moves smoothly in the bore.
Use Again


Illustration 235g03356140
Sleeve with discoloration on the land.
Use Again

c

Spool



Illustration 236g03356145
Use Again - If marks can be seen but not felt with a fingernail or pencil lead.


Illustration 237g03354074
Spool with polishing marks and discoloration on lands but spool moves smoothly in the bore.
Use Again


Illustration 238g03354077
Spool with scoring that can be felt with a fingernail or pencil lead.
Do Not Use Again

Piston Shaft Assembly



Illustration 239g03289101
Piston shaft teeth with even surface contact and no noticeable wear.
Use Again


Illustration 240g03354099
White spots in root of gear teeth that cannot be felt with a pencil lead.
Use Again


Illustration 241g03354102
Broken teeth caused by foreign debris.
Do Not Use Again


Illustration 242g03354104
Tooth damage caused by foreign debris.
Do Not Use Again


Illustration 243g02552724
Piston shaft assembly with no damage to drive gear.
Use Again


Illustration 244g03354107
Piston shaft assembly with damage to drive gear.
Do Not Use Again


Illustration 245g03354110
Piston shaft assembly with damage to piston sockets.
Do Not Use Again


Illustration 246g03354288
Piston shaft assembly with overheated piston sockets and fretting on drive gear.
Do Not Use Again


Illustration 247g03354297
Piston shaft assembly with polished piston sockets.
Use Again - If reuse criteria are met.


Illustration 248g02709677
Socket for center pin and pistons with no grooves or traces of seizing.
Use Again


Illustration 249g03354313
Socket for center pin with seizure. Reworking of the socket is not possible.
Do Not Use Again


Illustration 250g03354322
Socket for piston with seizure. Reworking of the socket is not possible.
Do Not Use Again


Illustration 251g03354328
Threaded holes in the flange of the drive shaft are undamaged.
Use Again

Drive Shaft

If the bearing surfaces are damaged, metal spray can be used to build up the worn area and the surface can be machined to a "like new" condition. If this reconditioning is used and the drive shaft meets all other reusability requirements, the shaft can be used again. oSee a thermal spray Reuse and Salvage Guideline found in the "References" section at the beginning of this document for more information.

Both splines must meet the minimum dimension of measurement over pins to be used again.

Check for thread damage to the tapped hole in the end of the drive shaft. This threaded hole is needed to pull the rotary group back against the retaining ring after being assembled in housing . The threaded hole can also be used for drawing the drive element (gear) onto the spline of the shaft.



Illustration 252g02796408
(1) Needle bearing surface
(2) Cylinder splines
(3) Roller bearing surface
(4) Seal area
(5) Input splines


Illustration 253g02691999
Drive Shaft nomenclature
(6) Blind threaded hole in drive shaft
(7) Splines
(8) Shaft seals surface
(9) Threads
(10) Bearing surface
(11) Threaded holes
(12) Socket


Illustration 254g03356151
The seal area and the roller bearing surface of the drive shaft, indicated by arrows, show wear which can be seen but not felt with a pencil lead or ufingernail.
Use Again


Illustration 255g03356157
Ball retainer and spacer area on the front shaft.
Use Again - If wear can be seen but cannot be felt with a fingernail or pencil lead.

The wear in the shaft seal area shown in Illustration 255 applies to both front and rear shafts. If damage to the seal area is present, metal spray can be used to restore the surface to a "like new" condition.



Illustration 256g02809399
Input splines on the drive shaft. Wear steps can be seen but not felt with a pencil lead or fingernail and the spline measurement over pins is acceptable.
Use Again


Illustration 257g03356163
Cylinder splines with visible wear steps which can be felt with a pencil lead or fingernail cannot be salvaged.
Do Not Use Again


Illustration 258g02709561
Drive shaft with no wear on spline. No wear steps can be seen. No wear steps can be felt with a pencil lead or fingernail.
Use Again


Illustration 259g03356191
Shaft with wear on the spline. Wear steps can be seen.
Do not use again


Illustration 260g02709572
Shaft wear on the seal surface that can be seen but cannot be felt with a pencil lead or finger nail.
Use Again


Illustration 261g02709635
Thread for slotted round nut with no damage. When reusing the drive shaft, brush off any Loctite residue.
Use Again


Illustration 262g03356423
Shaft with wear on the seal surface that can be felt with a pencil lead or finger nail. Refer to the "Procedure to Salvage Shaft Seal Area" section in this document.
Use Again - After the seal area is salvaged according to the correct procedure.


Illustration 263g03354541
Worn bearing seats on the drive shaft that can be felt with a pencil lead or fingernail.
Use Again - After the bearing area is salvaged and wear cannot be felt.


Illustration 264g03289060
Shaft of pinion gear that has no noticeable wear.
Use Again


Illustration 265g03354548
Shaft with damage to keyway and bearing area.
Do Not Use Again


Illustration 266g03356199
Shaft with damage to keyway.
Do Not Use Again


Illustration 267g03356206
Shaft with excessive spline wear.
Do Not Use Again


Illustration 268g03356232
Shaft with light spline wear.
Use Again


Illustration 269g02647324
Shaft with wear in the seal surfaces that can be seen but cannot be felt with a fingernail or pencil lead.
Use Again


Illustration 270g02647865
Shaft with wear on the splines. No wear steps can be seen.
Use Again


Illustration 271g03354551
Shaft with wear on the splines. Wear steps can be seen.
Do Not Use Again

Procedure to Inspect Shaft Seal Area



Illustration 272g03354557
Grooves in the seal area can be felt with a fingernail.
Use Again - After the seal area is salvaged according to the correct procedure

Procedure to Salvage Shaft Seal Area

Grooves in the seal area that can be felt with a fingernail, as shown in Illustration 272, can be removed to make the part usable again.

Note: Follow the metal spray manufacturer directions carefully in the application of metal spray to the shaft seal area.

The salvage procedure is as follows:

  1. Measure the shaft outside diameter at the seal area and the shoulder radius (if present) and make a note of each dimension.

  2. Worn or damaged surfaces designated as salvable by chrome plating can also be salvaged by a metal spray process. Metal spray is an acceptable method of restoring a surface to the original size. Each step in the procedure is critical in achieving the desired coating bond and surface finish. See any of the thermal spray Reuse and Salvage Guidelines found in the "References" section at the beginning of this document for more information.

  3. Grind the seal area to the diameter you measured in Step 1. The surface finish must be 0.40 to 0.80 µm (16 to 32 microinch). The wheel radius must be the same or greater than the shoulder radius measured in Step 1.

Spline Measurement



Illustration 273g02557136


Illustration 274g02647922
Measurement of the shaft splines.

If the splines have a visible wear step, the shaft cannot be used again. If necessary, measure the splines. Use two pins placed in the splines 180° apart. For shafts that have an odd number of spline teeth, put the pins in splines as near to 180° apart as possible. Put rubber bands around the pins and shaft to keep the pins in place. Refer to Illustrations 273 and 274. Refer to the manufacturer for reusability specifications for the pin diameter and the use again dimension. Use an outside diameter micrometer to measure across the pins. The crown splines must be measured at the center of the spline for the correct measurement. If measurement is less than the dimension given by the manufacturer, the shaft cannot be used again.

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