Off-Highway Truck Final Drive Planetary Carrier {0760, 0761, 4084} Caterpillar

Off-Highway Truck/Tractor

All

Introduction

Table 1

Revision	Summary of Changes in SEBF8752
08	Corrected dimension in Table 11 Column "A" Row 2. Removed old Point of Contacts. New Point of Contact added to the document. Updated copyright date to 2017.
07	Added nomenclature for 795 AC.
06	Changed dimensions to reflect correct imperial dimensions and improved illustrations.

© 2017 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. 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 technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) Interface.

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

This guideline provides information, which aids in the determination of final drive planetary carrier reusability. It also contains reusability specifications of critical planetary shaft dimensions. Use the inspection procedures and reusability examples provided in this guideline to determine whether the component may be reused or requires salvage operations. Never install a part that this guideline indicates should not be used again. In addition, the guideline provides salvage information and procedures for typical wear areas of final drive planetary carriers. The salvage procedures presented herein have been developed by Caterpillar Repair Process Engineering.

Important Safety Information

Illustration 1	g02139237

Work safely. 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. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.

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Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood 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.

The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The “WARNING” safety alert symbol is shown below.

Illustration 2	g00008666

This safety alert symbol means:

Pay attention!

Become alert!

Your safety is involved.

The message that appears under the safety alert symbol explains the hazard.

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. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

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

Service Letters and Technical Information Bulletins

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NOTICE
The most recent Service Letters and Technical Information Bulletins that are related to this component shall be reviewed before beginning work. Often Service Letters and Technical Information Bulletins contain upgrades in repair procedures, parts, and safety information that pertain to the parts or components being repaired.

References

Table 2

References
Media Number	Title
SEBF8163	Procedures to Salvage Thrust Faces on Planetary Carriers
SEBF8190	Tapered Bearings Used in Off-Highway Trucks
SEBF8193	Analysis and Assessment of Final Drive Gears Used in Off-Highway Trucks
SEBF8225	Reusability of Final Drive Splines on 785, 789, and 793 Off-Highway Trucks
SEBF8728	Specifications for Inspection of Driveline Fasteners
SEBF8759	Reusability of Final Drive Splines on 769- 784 Off Highway Trucks
SEBF9238	Fundamentals of Arc Spray for Reconditioning Components
SEBF9240	Fundamentals of Flame Spray for Reconditioning Components

Tooling and Equipment

Table 3

Required Tools
Part Number	Part Description
1P-3537	Dial Bore Gauge Kit
1U-5516	Discs (Coarse)
1U-5519	Disc Pad Holder
1U-6832	Abrasive Disc
1U-6846	Abrasive Disc
1U-9918	Wire Brush
4C-4079	Parts Cleaner
4C-4200	High Gloss Yellow Paint
4C-4804	Penetrant
4C-4805	Developer
4C-6796	Mineral Spirits
4C-8515	Flapper Wheel (2" x 1" 120 grit)
4C-8516	Flapper Wheel (2" x 1" 180 grit)
4C-8519	Flap Wheel 180 Grit
4C-8521	Wheel Adapter
5P-1720	Seal Pick
6V-2010	Polishing Stone
8S-2257	Eye Loupe
8T-5096	Dial Indicator Group
8T-7765	Non-metallic Scouring Pad
222-3071	Angle Die Grinder
222-3074	Medium Mini Die Grinder
222-3076	Right Angle Die Grinder
222-3077	Extended Die Grinder
223-1154	Metal Marking Pen (Air)
237-5181	Respirator
254-5307	Pad
254-5309	Pad
254-5329	Flapper Wheel (2" x 1" 180 grit)
254-5330	Flapper Wheel (2" x 1" 240 grit)
254-5342	Flap Disc
263-7184	Crack Detection Kit
385-9422	Inside Micrometer Set (2-24 inch)
459-0184	UV Lamp Kit
473–8688 or 473–8689	Inside Micrometer Set (2-12 inch)
	Inside Micrometer Set (50-300 mm)

Standardized Parts Marking

Reference: Refer to Reuse And Salvage Guideline, SEBF8187, "Standardized Parts Marking Procedures" for additional information regarding marking procedures.

Note: Use metal marking pen for all marking.

The procedure for marking includes a code that will identify the number of repairs and the number of hours on each repair.

Illustration 3	g03683915
Illustration 3 shows code (1-15). The first number (1) indicates that the component had been repaired once. The second number (15) indicates that there were 15,000 hours on the component at the time of repair.

Illustration 4	g03683920
Illustration 4 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second repair. The first number (2) indicates that the component had been repair twice. The second number (10) indicates that there were 10,000 hours on the component at the time of repair.

This coding can be used by all dealers and will help with identification at time of repair. Identification can be especially helpful if units that have been repaired are sold into different territories. As new overhauls are completed, the previous markings should be left on the part. To obtain the total number of hours for the component in Illustration, 4 you must add first and second repaired hours. In this example the component has a total of 22,000 hours.

Prepare the Area for Inspection

Illustration 5	g00008666

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Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using.

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Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.

Illustration 6	g03721203
Typical burr removal tooling. (A) Right Angle Die Grinder (B) Die Grinder (C) ( D) ( E) Conditioning Discs, Disc Pad Holder, and Threaded Shaft (F) ( G) Flapper Wheels

• Clean all surfaces for inspection before you inspect the part. Make sure that you remove all rust, dirt, paint, grease oil, and fluids or moisture

• During cleaning, do not damage machined surfaces.

• Use pressurized air to dry parts.

• Inspect nuts and bolts removed, refer to SEBF8728, "Specifications for Inspection of Driveline Fasteners" for further information.

Final Drive Group

Illustration 7	g03711610

Note: Final drive group (768 through 777). See Table 4 for item identification.

Table 4

Final Drive Nomenclature 768 through 777
Item	Description
(1)	Axle Shaft
(2)	Final Drive Hub
(3)	Planet Shaft (Pin)
(4)	Planet Gear
(5)	Ring Gear
(6)	Sun Gear
(7)	Planetary Gear
(8)	Cover Assembly

Illustration 8	g03711612

Note: Final drive group (784 through 793). See Table 5 for item identification.

Table 5

Final Drive Nomenclature 784 through 793
Item	Description
(1)	Axle Shaft
(2)	Final Drive Hub
(3)	First Reduction Sun Gear
(4)	First Reduction Planet Shaft
(5)	First Reduction Planet Gear
(6)	First Reduction Ring Gear
(7)	Cover
(8)	Second Reduction Sun Gear
(9)	Second Reduction Planet Shaft
(10)	Second Reduction Planet Gear
(11)	Second Reduction Ring Gear
(12)	First Reduction Planet Carrier
(13)	Second Reduction Planet Carrier

Illustration 9	g06058917

Note: Final drive group (795). See Table 7 for item identification.

Table 6

Final Drive Nomenclature 795
Item	Description
(1)	Final Drive Hub
(2)	First Reduction Sun Gear
(3)	First Reduction Planet Shaft
(4)	First Reduction Planet Gear
(5)	First Reduction Ring Gear
(6)	First Reduction Planet Carrier
(7)	Second Reduction Planet Carrier
(8)	Cover
(9)	Second Reduction Sun Gear
(10)	Second Reduction Planet Shaft
(11)	Second Reduction Planet Gear

Illustration 10	g03711616

Note: Final drive group (797). See Table 7 for item identification.

Table 7

Final Drive Nomenclature 797
Item	Description
(1)	Spindle
(2)	Final Drive Hub
(3)	First Reduction Sun Gear
(4)	First Reduction Planet Shaft
(5)	First Reduction Planet Gear
(6)	First Reduction Ring Gear
(7)	First Reduction Planet Carrier
(8)	Second Reduction Planet Carrier
(9)	Cover
(10)	Second Reduction Sun Gear
(11)	Second Reduction Planet Shaft
(12)	Second Reduction Planet Gear
(13)	Second Reduction Ring Gear

Planetary Carrier Reuse and Inspection

General Guidelines

Planetary carriers must be inspected prior to any salvage repair. The carrier should be inspected immediately after disassembly and cleaning. The critical features of the planetary carrier to be inspected are:

• Pin Bores

• Planetary Shafts (Pins)

• Thrust Surfaces

• Mounting Flange and Bolt Holes (Outer Carrier)

• Splines (Inner Carrier)

• Webs

Planetary Carrier Nomenclature

Illustration 11	g03711620

1. Pin Bore

2. Shaft (Pin)

3. Thrust Surface

4. Mounting Surface and Bolt Holes

5. Web
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   Illustration 12	g03711625

6. Splines

Planetary Carrier Identification

Illustration 13	g03711635
Typical Final Drive Planetary Carrier (768 through 777)

Illustration 14	g03711640
Typical Outer Planetary Carrier (784 through 793)

Illustration 15	g03711643
Typical Inner Planetary Carrier (784 through 793)

Illustration 16	g03711646
Inner Planetary Carrier (795)

Illustration 17	g03711649
Outer Planetary Carrier (795)

Illustration 18	g03711652
Typical Outer Planetary Carrier (797)

Illustration 19	g03711655
Typical Inner Planetary Carrier (797)

Pin Bore Reusability

Off-highway truck planetary carriers use two types of planet shafts or pins. Pins may be “slip-fit” or “press fit” pending on the application. Slip-fit pins are placed in the pin bore with little force and are retained by pins, bolts, and retainers or snap rings. Press fit pins must be pressed into the carrier bore. An interference fit exists between the press fit planet shaft and the pin bore. This design is used when higher loading is expected. Fasteners are used to retain the press fit pins.

Bores will usually show a shaft contact area that may be worn slightly. Other damage may include fretting, broaching, adhesive, and impact. Carriers should not be reused if any of the following conditions exist:

• The bore has a wear step that will stop a seal pick

• The shaft has spun in the bore.

• The bore is elongated or cracked.

• Significant fretting or broaching damage is present in the bore.

• The pin bore exceeds the as new specifications.

Inspection Procedure

Complete the following steps to inspect the pin bore.

1. Clean the pin bore thoroughly before inspecting. Pin bores and shafts (pins) can be cleaned with parts cleaner and a non-metallic scouring pad that will not remove metal.
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   Illustration 20	g03711664
   (1) Pin bore that has not been cleaned (2) Pin bore that has been cleaned

2. Visually inspect the bore for damage and wear.

   Note: An adequate light source should be used when inspecting pin bores. An optical magnifier (loupe) may also be used.

3. Inspect the bore with a seal pick to detect any wear steps.

4. Refer to reusability examples for pin bores, Illustrations 20 through 31.

5. Refer to Reusability Tables 8 through 12 for a summary of pin bore specifications. Compare these specifications to the actual measurements of the pin bores.

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NOTICE
Pin bore wear beyond new specifications is not permitted. Once wear begins, progression to complete failure can be rapid.

Fretting Wear

Illustration 21	g03711665
Typical Example (1) Normal appearance of the pin bore. Machining marks are visible. (2) A narrow band where the pin did not contact the bore is visible, but no wear step exists.

Illustration 22	g03711667
Typical Example (1) Slight wear step that does not stop the seal pick. Use again if the pin bore is within the dimensional specifications.

Use Again

Illustration 23	g03711674
(1) Fretting damage on the pin bore. Refer to Illustration 23.

Use Again

Fretting wear is allowed on the pin bore if the following conditions are met. The fretting wear may not:

1. Be greater than 50% of the bore width

2. Be greater than 25% of the bore diameter.

Illustration 24	g03711679
(1) Pin has fretting wear that matches the pin bore. Refer to Illustration 24.

Illustration 25	g03711680
(1) Light fretting usually will not stop the seal pick. (2) The arrow indicates direction of pick travel.

Use Again

Broaching Wear

Illustration 26	g03711683
(1) Light broaching is acceptable.

Use Again

Broaching can be the result of fretting, debris damage, handling damage, or other shaft features that scratch the bore during installation, operation, and/or removal.

Illustration 27	g03711684
(1) Maximum allowed broaching wear. Several scratches are wide and cross the entire bore. Machining marks are still visible under the scratches.

Use Again

Illustration 28	g03711692
Significant fretting and broaching wear.

Do Not Use Again

Spun Planet Shaft (Pin)

Illustration 29	g03711695

There may be markings on the planet shaft and carrier identifying the original position of the pin in the bore. If the marks are not aligned, that is an indication that the pin has spun in the bore. The shaft and/or carrier will need to be repaired or replaced.

Note: Remember to mark (or remark) the planet shafts and carrier during assembly after inspection/salvage.

Illustration 30	g03711699
The pin has spun in the bore. Significant radial scratches and adhesive wear are present.

Do Not Use Again

Elongated Pin Bore

Illustration 31	g03711703
(1) Inspect for elongated bores while the planet shafts are installed.

Compare the clearances at the positions indicated in Illustration 31 prior to shaft disassembly. Do not reuse the planetary carrier if the bore is elongated or cracked. Following removal of the shaft, measure the bore to ensure that the bore meets the specifications presented in Reusability Tables 8 through 12.

Planetary Shafts (Pins) Reusability

Off-highway truck planetary carriers use two types of planet shafts or pins. Pins may be “slip-fit” or “press fit” depending on the application. Slip-fit pins are placed in the pin bore with little force and are retained by pins, bolts, and retainers, or snap rings. Press fit pins must be pressed into the carrier bore and retained by fasteners.

Planetary Shafts will usually show a pin bore contact area that may be worn slightly. Damage may include fretting, broaching, adhesive, and impact. Shafts cannot be reused if any of the following conditions exist:

• The shaft has a wear step that will stop a seal pick.

• The shaft has spun in the bore.

• Significant fretting or broaching damage is present on the shaft.

• The shaft exceeds the as new specifications.

Inspection Procedure

Complete the following steps to inspect the planetary shaft.

1. Clean the shaft thoroughly before inspecting. Shaft (pins) can be cleaned with parts cleaner and a non-metallic scouring pad that will not remove metal.

2. Visually inspect the shaft for damage and wear.

   Note: An adequate light source should be used when inspecting planetary shafts. An optical magnifier (loupe) may also be used.

3. Inspect the shaft with a seal pick to detect any wear steps.

4. Refer to reusability examples for the press fit shafts, Illustrations 32 through 36, or for slip fit shafts, Illustrations 37 through 49.

5. For a summary of planetary shaft specifications, refer to Reusability Table 13. Compare these specifications to the actual measurements of the planetary shafts.

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NOTICE
Shaft wear beyond new specifications is not permitted. Once wear begins, progression to complete failure can be rapid.

Press Fit Shafts

Illustration 32	g03711711
Typical “press fit” shaft.

Press fit shafts are pressed into the bore in the carrier for an interference fit. This design is used where higher loads are expected and will also use fasteners to retain the shaft in the bore.

Illustration 33	g03711713
(1) Typical fretting on a press fit shaft.

Use Again

Illustration 34	g03711716
Typical fretting on a press fit shaft.

Use Again

Fretting occurs in shaft to carrier contact surfaces. Shafts can be reused if less than 50% of the contact width and 25% of the shaft diameter is affected. The shaft measurements must be within specifications.

Illustration 35	g03711717
(1) Press fit planetary shaft with handling damage.

Do Not Use Again

Do not reuse shafts with significant handling damage.

Illustration 36	g03711718
(1) Press fit shaft with typical wear on mounting areas. Bearing may have been rotated on shaft.

If shaft mounting areas appear worn, measure and check specifications before reuse.

Slip Fit Shafts

Illustration 37	g03711720
Typical “slip fit” shaft.

Slip fit shafts can be installed and removed without a press. Slip fit shafts are used with three types of planetary bearings.

• Sleeve bearing

• Straight roller bearing with inner race

• Straight roller bearing without inner race

Illustration 38	g03711721
Slip fit shaft for use with a sleeve bearing.

Illustration 39	g03711725
Slip fit shaft for use with a straight roller bearing with inner race.

Illustration 40	g03711727
Damaged slip fit shaft from a sleeve bearing application.

Planet shafts for sleeve bearing applications:

Do Not Use Again

• Must not have adhesive wear or smearing

• Should not be temper colored from high temperature operation

• Should not have abrasive wear

• May be lightly polished from sleeve contact

• May show carrier contact areas at ends

This design is more sensitive to speed and load than designs using anti-friction bearings.

Illustration 41	g03711728
Damaged slip fit shaft from sleeve bearing application.

Do Not Use Again

Illustration 42	g03711730
Typical wear on slip fit shaft from a straight roller bearing application.

Use Again

Straight roller bearings with inner races will have a slight interference fit with the shaft and will leave a discolored area on shaft where mounted.

Do not reuse if the bearing race has spun on the shaft.

Illustration 43	g03711731
Slip fit shaft from straight roller bearing application with no race.

In some applications the planet shaft also provides the inner race for the straight roller bearing. For off-highway trucks in extreme load applications, Caterpillar does not recommend final drive planetary shaft reuse. Replace shafts and bearings together in those applications.

If not used in an extreme high load application, the planet shaft may be reused if the following criteria is met:

• Rollers contact areas may have a dull appearance due to roll burnishing during normal operation

• Shaft must not have wear steps, abrasive or adhesive wear, pitting, handling damage, significant debris damage.

• Shaft should measure within normal specifications

Illustration 44	g03711732
Slip fit shaft from straight roller bearing application with no inner race. Shaft has mild debris bruising.

Use Again

Illustration 45	g03711734
Slip fit shaft from straight roller bearing application with no inner race. Shaft has maximum allowable debris bruising

Use Again

Illustration 46	g03711735
Slip fit shaft from straight roller bearing application with no race. (1) Large dents are found on the surface of the shaft.

The dents on the surface of the shaft are too large. If reused, pitting will initiate around the dents.

Do Not Use Again

Illustration 47	g03711736
Slip fit shaft from straight roller bearing application with no race. (1) Old bruises (dark spots) (2) Pitting (light-colored areas)

Do Not Use Again

Illustration 48	g03711737
Slip fit shaft from straight roller bearing application with no race. Brinelling is visible on the shaft where it has been dented by the bearing roller.

Do Not Use Again

Thrust Pad Reusability

Note: Thrust faces of final drive planetary carriers can be damaged by foreign material or by the failure of a washer. Refer to Reuse and Salvage, SEBR8163, "Procedures to Salvage Thrust Faces on Planetary Carriers" to repair damaged faces of planetary carriers.

768 through 797 Off Highway Truck planet gears are designed to use tapered or straight roller anti-friction bearings. Carriers using slip fit shafts typically have thrust pads on both sides of the gear with straight roller anti-friction bearings and require thrust washers. Refer to Illustration 49. Carriers using press fit shafts typically have thrust pads on one side only with tapered roller bearings and do not require thrust washers. Refer to Illustration 50.

Illustration 49	g03711739
(1) Planet gear with thrust pads and thrust washers on both sides.

Illustration 50	g03711741
(2) Planetary carrier with thrust pads on a single side.

Carriers with Slip Fit Shafts

Carriers with slip fit planetary shafts use straight roller bearings with thrust washers and thrust pads on both sides of the bearings.

• Planetary shafts are slipped into place during assembly and hold the straight roller bearings between the thrust washers.

• When thrust washers are used, thrust pad wear and/or damage is critical. Only mild wear, about, 0.127 mm (0.005 inch) wear step is allowed. The thrust surface must be smooth to be reused.

Carriers with Press Fit Shafts

Carriers with press fit planetary shafts may use either tapered or straight roller bearings with one thrust pad and do not use thrust washers.

• The planetary shafts are pressed in place during assembly and hold the tapered or straight roller bearings between the shaft head and the carrier thrust pad. Shaft retainers are shimmed to apply a specific preload on the bearings.

• Thrust pads can wear until the depth from the planet shaft end and retainer end bore is too small to meet shim pack requirements, and the bearings can no longer be preloaded.

Inspection Procedure

Complete the following steps to inspect the planetary carrier thrust pads.

1. Clean the thrust pad thoroughly before inspecting. Thrust pads can be cleaned with parts cleaner and non-metallic scouring pad that will not remove metal

2. Visually inspect the thrust pad for damage and wear.

   Note: An adequate light source should be used when inspecting thrust pads. An optical magnifier (loupe) may also be used.

3. Inspect the thrust pads with a seal pick to detect any wear steps. (Only necessary for slip fit applications. Thrust pads used in press fit applications can experience more wear and may still be reused as long as the bearings seat properly).

4. Refer to reusability examples for carriers using slip fit shafts, Illustrations 51 through 55 or for carriers using press fit shafts, Illustrations 56 through 60.
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   NOTICE
   Criteria for reuse of thrust pad varies depending on the use of thrust washers. Some damage to thrust pads that may be acceptable on press fit applications may not be acceptable on slip fit applications. Refer only to reusability examples pertaining to your particular application.

5. Refer to Reusability Tables 8 through 12 for a summary of thrust pad specifications located at the end of Reuse and Inspection section. Compare these specifications to the actual measurements of the carrier thrust pads.

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NOTICE
Thrust pad wear beyond new specifications is not permitted. Once wear begins, progression to complete failure can be rapid.

Reuse Examples for Carriers with Slip Fit Shafts

Illustration 51	g03711800
Planetary carrier with thrust pads and thrust washers on both sides.

Illustration 52	g03711801
Normal used appearance of thrust pad used with thrust washers.

Use Again

Illustration 53	g03711803
Thrust pad used with washers. Polish lightly to remove burrs and smooth surface.

Use Again

Illustration 54	g03711805
Thrust pad used with thrust washers. Remove burrs, rough edges, and raised material around damaged area, smooth surface with 6V-2010 stone. The thrust pad may be used again if still within specifications after cleanup of the face.

Use Again

Illustration 55	g03711806
Severe debris damage to thrust pad used with thrust washers.

Do Not Use Again

Reuse Examples for Carriers with Press Fit Shafts

Illustration 56	g03711807
Planetary carrier with thrust pad on one side.

Illustration 57	g03711808
Typical Off Highway Truck new or salvaged thrust pad appearance.

Use Again

Illustration 58	g03711809
Typical thrust pad wear. A wear step is evident, however, no pitting or spalling is detected.

The thrust pad depicted in Illustration 58 may be used again as long as the planet shaft is not flush with the retainer end bore. Before and during assembly, be sure that the new bearing inner race seats into the worn area correctly to ensure that preload is maintained during operation.

Use Again

Illustration 59	g03711811
Advanced thrust pad wear and fretting.

Although the thrust pad appears damaged, thrust pad may be reused in this condition as long as the bearings will seat properly and can be preloaded in this press fit application.

Use Again

Illustration 60	g03711812
Measuring for shim pack depth.

Illustration 60 shows measuring for shim pack required to obtain correct bearing preload depending on the application. Refer to the planetary carrier assembly section of the appropriate Disassembly and Assembly manual for shim pack requirements. If the thrust pad has too much wear to meet shim pack requirements, thrust pad cannot be reused.

Note: Excessive wear to the bearings or pin shoulder beyond “as new” specifications may also be the cause of failure to meet shim pack requirements.

Thrust Washer Reusability

Planetary carriers using slip fit shafts have thrust washers between the thrust pad and bearing. All current Off Highway Truck models use plastic thrust washers, however, some machines may still have metal washers in the planetary carriers.

Illustration 61	g03711815
Plastic (left) and metal (right) thrust washers from final drive planetary carriers.

Plastic washers should always be replaced at rebuild. If possible, metal washers should also be replaced, but may be reused if the following requirements are fulfilled:

• Contact surfaces should not have deep wear grooves, steps, or adhesive smearing.

• Debris damage on thrust faces should cover less than 10% of the face.

• Contact surfaces should not have embedded debris.

• Washers may be discolored from heat, but should not be reused if ran excessively hot (black with oxidized oil stains on the surfaces).

Illustration 62	g03711817
Wear step on thrust washer.

Do Not Use Again

Illustration 63	g03711822
Thrust washer with heat discoloration and embedded debris. Some discoloration from heat is acceptable, but do not reuse if other damage is present.

Do Not Use Again

Mounting Flange and Bolt Holes

Illustration 64	g03711823
(1) Planetary carrier mounting flange

Observe mounting flanges for significant fretting. Check each bolt hole carefully for wear and cracking.

Illustration 65	g03711825
(1) Cracked bolt hole

Do Not Use Again

768 through 797 Off Highway Truck Planetary Carriers are a casting of ductile iron. Currently there is no recommended weld fill procedure to repair damaged mounting flange bolt holes on ductile iron castings. Until further salvage procedures are developed, Caterpillar recommends replacing carriers with cracked bolt holes.

Planetary Carrier Splines

The high loading on Off Highway Truck planetary carrier splines can cause wear, fatigue cracks, or misalignment. If wear is minimal, it may be possible to reuse the splines. Reuse information and salvage procedures are available in:

• Reuse and Salvage Guideline, SEBF8225, "Reusability of Final Drive Splines on 785, 789, 793 and 797 Off Highway Trucks."

• Reuse and Salvage Guideline, SEBF8759, "Reusability of Final Drive Splines on 769-784 Off Highway Trucks."

Web Cracks

Some planetary carriers may crack at the inner and outer deck separator webs after a length of time. Do not reuse a carrier with a cracked web. Do not attempt to repair a cracked carrier. Welding is not recommended on cast ductile iron planetary carriers in Off-Highway Trucks.

Reusability Tables

Illustration 66	g03711826
768 through 777 Pin Bore Cross Section with Dimensions

(A & B) Pin Bore Diameters

(C) Counterbore Diameter

(D) Pocket Width

(E) Thrust Face Depth

(G) Thrust Face Diameter

Illustration 67	g03711827
768 through 777 Typical Final Drive Outer Planetary Carrier

(H) Carrier Diameter

(I, J & K) Pin Bore Locations

Table 8

768 through 777 Final Drive Outer Planetary Carrier Dimensions (Refer to Illustrations 66-67)
Carrier Part Numbers	A	B	C	D	E	G	H	I	J	K
212-3479, 5D-9739, 278-0174	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	84.8 ± 0.5 mm (3.3386 ± 0.0197 inch)	112.62 ± 0.1 mm (4.4339 ± 0.0039 inch)	16.46 mm (0.6480 inch)	127.00 mm (4.9999 inch)	551 ± 0.5 mm (21.6929 ± 0.0197 inch)	138.552 mm (5.4548 inch)	119.99 mm (4.7240 inch)	69.276 mm (2.7274 inch)
5D-4833	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	84.8 ± 0.5 mm (3.3386 ± 0.0197 inch)	112.62 ± 0.1 mm (4.4339 ± 0.0039 inch)	16.46 mm (0.6480 inch)	127.00 mm (4.9999 inch)	551 ± 0.5 mm (21.6929 ± 0.0197 inch)	138.552 mm (5.4548 inch)	119.99 mm (4.7240 inch)	69.276 mm (2.7274 inch)
7D-2809	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	98.6 ± 0.5 mm (3.8819 ± 0.0197 inch)	118.97 mm (4.6839 inch)	19.84 mm (0.7811 inch)	146.00 mm (5.7480 inch)	632 mm (24.8818 inch)	159.868 mm (6.2940 inch)	138.45 mm (5.4508 inch)	79.934 mm (3.1470 inch)
212-3480, 9D-8794, 391-4086	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	98.6 ± 0.5 mm (3.8819 ± 0.0197 inch)	118.97 mm (4.6839 inch)	19.84 mm (0.7811 inch)	146.00 mm (5.7480 inch)	632 mm (24.8818 inch)	159.868 mm (6.2940 inch)	138.45 mm (5.4508 inch)	79.934 mm (3.1470 inch)
6D-6574, 5T-5746	101.686 ± 0.013 mm (4.0034 ± 0.0005 inch)	101.686 ± 0.013 mm (4.0034 ± 0.0005 inch)	N/A	118.97 ± 0.10 mm (4.6839 ± 0.0039 inch)	11.2 ± 0.5 mm (0.4409 ± 0.0197 inch)	180 mm (7.0866 inch)	947 mm (37.2834 inch)	228.239 mm (8.9858 inch)	197.661 mm (7.7819 inch)	114.12 mm (4.4929 inch)
212-3481, 2G-6203, 282-2482	101.686 ± 0.013 mm (4.0034 ± 0.0005 inch)	101.686 ± 0.013 mm (4.0034 ± 0.0005 inch)	N/A	138.02 mm (5.4339 inch)	11.2 ± 0.5 mm (0.4409 ± 0.0197 inch)	181 mm (7.1260 inch)	952.5 mm (37.4999 inch)	232.766 mm (9.1640 inch)	201.582 mm (7.9363 inch)	116.383 mm (4.5820 inch)
257-8532	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	77.605 ± 0.013 mm (3.0553 ± 0.0005 inch)	84.8 ± 0.5 mm (3.3386 ± 0.0197 inch)	112.62 ± 0.1 mm (4.4339 ± 0.0039 inch)	16.46 mm (0.6480 inch)	127.00 mm (4.9999 inch)	554 ± 2 mm (21.8110 ± 0.0787 inch)	138.552 mm (5.4548 inch)	119.99 mm (4.7240 inch)	69.276 mm (2.7274 inch)
314-9074	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	89.253 ± 0.013 mm (3.5139 ± 0.0005 inch)	98.6 ± 0.5 mm (3.8819 ± 0.0197 inch)	126.97 mm (4.9988 inch)	19.84 mm (0.7811 inch)	146.00 mm (5.7480 inch)	632 mm (24.8818 inch)	160.153 mm (6.3052 inch)	138.696 mm (5.4605 inch)	80.077 mm (3.1526 inch)

Reusability Tables

Illustration 68	g03711851
784 through 793 Pin Bore Cross Section with Dimensions

(A & B) Pin Bore Diameters

(C) Counterbore Diameter

(D) Pocket Width

(F) Thrust Face Depth

(G) Thrust Face Diameter

784 through 793 Inner Planetary Gear

Illustration 69	g03711852
784 through 793 Typical Final Drive Outer Planetary Carrier

(H) Carrier Diameter

(I & J) Pin Bore Locations

Table 9

784 through 793 Final Drive Outer Planetary Carrier Dimensions (Refer to Illustrations 68 through 69)
Carrier Part Numbers	A	B	C	D	F	G	H	I	J
8W-1365, 8X-6828, 261-1688	103.961 ± 0.013 mm (4.0929 ± 0.0005 inch)	85.013 ± 0.013 mm (3.3470 ± 0.0005 inch)	112 ± 0.5 mm (4.4094 ± 0.0197 inch)	134 mm (5.2756 inch)	31 mm (1.2205 inch)	113 mm (4.4488 inch)	1054 ± 0.08 mm (41.4960 ± 0.0032 inch)	287.576 mm (11.3219 inch)	287.576 mm (11.3219 inch)
8X-0603, 164-0288, 200-6387	130.923 ± 0.013 mm (5.1544 ± 0.0005 inch)	101.549 ± 0.013 mm (3.9980 ± 0.0005 inch)	133 ± 1 mm (5.2362 ± 0.0394 inch)	157.5 mm (6.2008 inch)	30 mm (1.1811 inch)	140 mm (5.5118 inch)	1177.8 ± 0.25 mm (46.36999 ± 0.0098 inch)	299.89 mm (11.8067 inch)	299.89 mm (11.8067 inch)

Illustration 70	g03711878
784 through 793 Pin Bore Cross Section with Dimensions

(A & B) Pin Bore Diameters

(C) Counterbore Diameter

(D) Pocket Width

(F) Thrust Face Depth

(G) Thrust Face Diameter

Illustration 71	g06058940
784 through 793 Typical Final Drive Inner Planetary Carrier

(H) Carrier Diameter

(I & J) Pin Bore Locations

Table 10

784 through 793 Final Drive Inner Planetary Carrier Dimensions (Refer to Illustrations 70 through 71)
Carrier Part Number	A	B	C	D	F	G	H	I	J
8W-3120	102.00 ± 0.013 mm (4.0157 ± 0.0005 inch)	77.775 ± 0.013 mm (3.0620 ± 0.0005 inch)	116.00 ± 1 mm (4.5669 ± 0.0394 inch)	100.5 mm (3.9567 inch) MIN	18.00 ± 0.05 mm (0.7087 ± 0.0020 inch)	106 mm (4.1732 inch)	666.00 mm (26.2204 inch)	257.81 mm (10.1500 inch)	257.81 mm (10.1500 inch)
8X-5059, 7I-5595, 141-0203, 197-2968	102.00 ± 0.013 mm (4.0157 ± 0.0005 inch)	77.775 ± 0.013 mm (3.0620 ± 0.0005 inch)	116.00 ± 1 mm (4.5669 ± 0.0394 inch)	102.5 mm (4.0354 inch)	18.00 ± 0.05 mm (0.7087 ± 0.0020 inch)	106 mm (4.1732 inch)	660 mm (25.9842 inch)	235.45 mm (9.2697 inch)	235.45 mm (9.2697 inch)

Reusability Tables

Illustration 72	g03711901
795 through 797 Pin Bore Cross Section with Dimensions

(A & B) Pin Bore Diameters

(D) Pocket Width

(F) Thrust Face Depth

(G) Thrust Face Diameter

Illustration 73	g03711907
795 through 797 Typical Final Drive Outer Planetary Carrier

(H) Carrier Diameter

(I & J) Pin Bore Locations

Table 11

795 through 797 Final Drive Outer Planetary Carrier Dimensions (Refer to Illustrations 72 through 73)
Carrier Part Number	A	B	D	F	G	H	I	J
139-7653	155.911 ± 0.013 mm (6.1382 ± 0.0005 inch)	129.936 ± 0.013 mm (5.1156 ± 0.0005 inch)	230 mm (9.0551 inch)	65 mm (2.5591 inch)	178 mm (7.0079 inch)	1273 ± 0.25 mm (50.1180 ± 0.0098 inch)	344.87 mm (13.5775 inch)	344.87 mm (13.5775 inch)
292-0251	196.253 ± 0.018 mm (7.72648 ± 0.0007 inch)	164.987 ± 0.018 mm (6.4955 ± 0.0007 inch)	220 mm (8.6614 inch)	61.7 mm (2.4291 inch)	N/A	970 mm (38.1889 inch)	325.86 mm (12.8291 inch)	325.86 mm (12.8291 inch)

Illustration 74	g03711921
795 and 797 Pin Bore Cross Section with Dimensions

(A & B) Pin Bore Diameters

(E & F) Thrust Face Depths

(G) Thrust Face Diameter

Illustration 75	g03711926
795 Final Drive Inner Planetary Carrier

(H) Carrier Diameter

(I, J & K) Pin Bore Locations

Illustration 76	g03711929
797 Final Drive Inner Planetary Carrier

(H) Carrier Diameter

(I & J) Pin Bore Locations

Table 12

795 through 797 Final Drive Inner Planetary Carrier Dimensions (Refer to Illustrations 74 through 76)
Carrier Part Number	A	B	E	F	G	H	I	J	K
139-7639	130.923 ± 0.013 mm (5.1544 ± 0.0005 inch)	101.549 ± 0.013 mm (3.9980 ± 0.0005 inch)	125 mm (4.9213 inch)	265.5 mm (10.4527 inch), 263.5 mm (10.3740 inch) MIN	138 mm (5.4331 inch)	785 mm (30.9055 inch) (1)	281.045 mm (11.0647 inch) (1)	281.045 mm (11.0647 inch) (1)	N/A
355-5850	101.549 ± 0.013 mm (3.9980 ± 0.0005 inch)	130.923 ± 0.013 mm (5.1544 ± 0.0005 inch)	90.5 mm (3.5630 inch)	236 mm (9.2913 inch)	139.9 mm (5.5079 inch)	980 mm (38.5826 inch) (2)	314.51 mm (12.3823 inch) (2)	272.376 mm (10.7234 inch) (2)	157.257 mm (6.1912 inch) (2)

(1)	Refer to Illustration 76
(2)	Refer to Illustration 75

Reusability Tables

768 through 797 Planetary Shafts

Illustration 77	g03711943
Typical press fit planetary shaft

Illustration 78	g03711945
Typical slip fit planetary shaft

Illustration 79	g03711949
Typical slip fit planetary shaft

Illustration 80	g03711952
Typical slip fit planetary shaft

Table 13

Off Highway Truck Final Drive Planetary Shaft Dimensions
Shaft	Illustration	L	M	N	O
9M-3821, 2G-7594, 5T-1266, 212-3476, 8X-5689, 242-5414	80	169.7 ± 0.5 mm (6.6811 ± 0.0197 inch)	77.577 ± 0.013 mm (3.0542 ± 0.0005 inch)	N/A	N/A
7D-2861, 2G-7592, 8W-5447, 212-3477, 8X-5699	80	169.7 ± 0.5 mm (6.6811 ± 0.01968 inch)	89.225 ± 0.010 mm (3.5128 ± 0.0004 inch)	N/A	N/A
4D-0445, 2G-6569, 101-1503	80	178.8 ± 0.5 mm (7.0394 ± 0.0197 inch)	101.661 ± 0.008 mm (4.0024 ± 0.0003 inch)	N/A	N/A
2G-7593, 8W-1691, 8X-1459, 8X-3932, 8X-7164, 212-3478, 102-2236	80	207.3 ± 0.5 mm (8.1614 ± 0.0197 inch)	101.661 ± 0.010 mm (4.0024 ± 0.0004 inch)	N/A	N/A
334-3372	80	182.8 ± 0.5 mm (7.1968 ± 0.0197 inch)	89.225 ± 0.010 mm (3.5128 ± 0.0004 inch)	N/A	N/A
7I-5540	77	138.6 ± 0.5 mm (5.4567 ± 0.0197 inch)	77.839 ± 0.012 mm (3.0645 ± 0.0005 inch)	114.743 ± 0.050 mm (4.5174 ± 0.0020 inch)	102.039 ± 0.012 mm (4.0173 ± 0.0005 inch)
8W-6909, 8X-8412	77	138.6 ± 0.5 mm (5.4567 ± 0.0197 inch)	77.903 ± 0.012 mm (3.0670 ± 0.0005 inch)	115.124 ± 0.050 mm (4.5324 ± 0.0020 inch)	102.039 ± 0.012 mm (4.0173 ± 0.0005 inch)
8W-3073	77	139.4 ± 0.5 mm (5.4882 ± 0.0197 inch)	77.839 ± 0.012 mm (3.0645 ± 0.0005 inch)	115.886 ± 0.050 mm (4.5624 ± 0.0020 inch)	102.039 ± 0.012 mm (4.0173 ± 0.0005 inch)
197-3090	77	139.4 ± 0.5 mm (5.4882 ± 0.0197 inch)	77.839 ± 0.012 mm (3.0645 ± 0.0005 inch)	115.886 ± 0.050 mm (4.5624 ± 0.0020 inch)	102.039 ± 0.012 mm (4.0173 ± 0.0005 inch)
139-7642	77	208.98 ± 0.5 mm (8.2275 ± 0.0197 inch)	101.651 ± 0.012 mm (4.0020 ± 0.0005 inch)	174.48 ± 0.5 mm (6.8693 ± 0.0197 inch)	131.012 ± 0.012 mm (5.1579 ± 0.0005 inch)
297-4874	77	205 mm (8.0709 inch)	101.651 ± 0.012 mm (4.0020 ± 0.0005 inch)	174.5 mm (6.8701 inch)	131.012 ± 0.012 mm (5.1579 ± 0.0005 inch)
302-0379	77	352.656 mm (13.8841 inch)	165.058 ± 0.012 mm (6.4983 ± 0.0005 inch)	299.656 mm (11.7975 inch)	196.342 ± 0.012 mm (7.7300 ± 0.0005 inch)
8W-3250, 8X-5726, 8X-7165	79	215.2 ± 0.5 mm (8.4724 ± 0.0197 inch)	101.661 ± 0.010 mm (4.0024 ± 0.0004 inch)	N/A	N/A
8X-6833	77	195.3 mm (7.6890 inch)	85.077 ± 0.012 mm (3.3495 ± 0.0005 inch)	160.66 mm (6.3252 inch)	104.00 ± 0.012 mm (4.0945 ± 0.0005 inch)
8X-0565	77	222.8 mm (8.7716 inch)	101.715 ± 0.012 mm (4.0045 ± 0.0005 inch)	181.85 mm (7.1594 inch)	131.012 ± 0.012 mm (5.1579 ± 0.0005 inch)
7I-5534, 197-5215	77	222.8 mm (8.7716 inch)	101.651 ± 0.012 mm (4.0020 ± 0.0005 inch)	181.85 mm (7.1594 inch)	131.012 ± 0.012 mm (5.1579 ± 0.0005 inch)
139-7654	77	333.7 mm (13.1378 inch)	130.038 ± 0.012 mm (5.1196 ± 0.0005 inch)	287.7 mm (11.3268 inch)	156.00 ± 0.012 mm (6.1417 ± 0.0005 inch)

Planetary Carrier Salvage

Thermal Spray Repair

Flame spray and arc spray are both acceptable thermal spray operations for repairing planetary carrier pin bores and thrust faces

• Reuse and Salvage, SEBF9238, "Fundamentals of Arc Spray for Reconditioning Components", provides arc spray recommendations and contains arc spray applications for the planet carrier pin bores and thrust faces.

• Reuse and Salvage, SEBF9240, "Fundamentals of Flame Spray for Reconditioning Components", provides flame spray recommendations and contains flame spray applications for planetary carrier pin bores and thrust faces.

Note: Only Caterpillar dealers utilizing thermal spray equipment "in house" are allowed use of the thermal spray applications.

Illustration 81	g03711978
Example of pin bore salvage using the arc spray procedure.

Crack Detection Methods

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NOTICE
Regardless of which crack detection method is used, it is important that the instructions furnished with the detection equipment are followed closely when checking any parts. Failure to do so may cause inaccurate results.

Inspection personnel can reference ASTM E165 and E709 for further details on inspection processes.

Personnel who perform examinations in accordance with this guide shall be qualified and certified. Individuals must be certified for Magnetic Particle Inspection at a minimum Level I in accordance with ASNT Recommended Practice No. SNT-TC-1A or ASNT CP-189.

Crack detection methods commonly used are liquid penetrant, dry magnetic particle, wet magnetic particle, and ultrasonic testing. There may be more than one acceptable crack detection method for the inspection of a given part, although the liquid penetrant is the most versatile. Select the method that best fits your shop's operation. Sometimes, characteristics of a particular part may prevent the use of certain inspection systems.

For example, a liquid penetrant system cannot be used to inspect for subsurface cracks in a steel part. Use Table 14 to determine the best system for the type of structure being inspected. The wet magnetic particle inspection method is best used when inspecting smooth machined components such as shafts, gear teeth, and splines. If the wet magnetic particle inspection method is not available, it can be substituted with the liquid penetrant examination method.

Table 14

Crack Inspection Method Advantages vs. Disadvantages
Inspection Method	Advantages	Disadvantages
Liquid Penetrant	- Least expensive - Minimal training - Portable - Works on nonmagnetic material	- Least sensitive - Detects surface cracks only
Dry Magnetic Particle	- Portable - Fast	- Works on magnetic material only - Less sensitive than Wet Magnetic Particle
Wet Magnetic Particle	- More sensitive than Liquid Penetrant - Detects subsurface as much as 0.13 mm (0.005 inch)	- Requires Power for Light - Works on magnetic parts only - Liquid composition and agitation must be monitored
Ultrasonic Testing	- Most sensitive - Detects deep material defects	- Most expensive - Requires operator training and certification

Liquid Penetrant Examination

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Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals.

Materials and Equipment Required

Refer to Tooling and Equipment Table 3 for part numbers.

• Cleaner: Removes dirt before dye application and dissolves the penetrant making possible to wipe the surface clean.

• Penetrant: This solution is highly visible, and will seep into openings at the surface of a part with capillary action.

• Developer: Provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrant indications.

• Wire Brush: Removes dirt and paint.

• Cloth or Wipes: Use with cleaner and for other miscellaneous uses.

Procedure

Illustration 82	g03791241

1. Preclean inspection area. Spray on cleaner to loosen any scale, dirt, or any oil. Wipe the area to inspect with a solvent dampened cloth to remove remaining dirt and allow the area to dry. If there is visible crack remove paint using paint remover or wire brush.
   Show/hide table

   Illustration 83	g03791250

2. Apply penetrant by spraying to the entire area to be examined. Allow 10 to 15 minutes for penetrant to soak. After the penetrant has been allowed to soak, remove the excess penetrant with clean, dry wipe.
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   Illustration 84	g03791397

3. The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
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   Illustration 85	g03791251

4. Before using developer make sure that, it is mixed thoroughly by shaking can. Holding can approximately 8-12 inches away from part, apply an even, thin layer of developer over the area being inspected. A few thin layers are a better application method than one thick layer.
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   Illustration 86	g03510598

5. Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as (A) red lines in white developer background. Clean the area of application of the developer with solvent cleaner.

Dry Magnetic Particle Inspection

Materials and Equipment Required

• Crack Detection Kit

Illustration 87	g03536204

(A) Indications shown by magnetic particle testing.

(B) Typical electromagnetic yoke.

(C) Dry powder bulb.

1. Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.

2. Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.

3. Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.

4. Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least 4.5 kg (10 lb).

5. Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.

6. All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.

Procedure

1. Insure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.

2. Apply the magnetic field using the yoke against the faces and inside diameter of each bore.

3. Simultaneously apply the dry powder using the dry powder blower.

4. Remove excess powder by lightly blowing away the dry particles.

5. Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.

6. Observe particles and note if any clusters of particles appear revealing an indication.

7. Record the size and shape of any discontinuities or indications found.

Wet Magnetic Particle Inspection

Materials and Equipment Required

• Crack Detection Kit

• UV Lamp Light

Illustration 88	g03536207

(A) Indications shown by magnetic particle testing.

(B) Typical electromagnetic yoke.

(D) UV lamp used in wet/liquid magnetic particle inspection process.

1. Wet magnetic particles are fluorescent and are suspended in a vehicle in a given concentration that will allow application to the test surface by spraying.

2. Concentration:

   1. The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.
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      Illustration 89	g03801656

   2. Concentrations are determined by measuring the settling volume by using an ASTM pear shaped centrifuge tube with a 1 mL (0.034 oz) stem with 0.05 mL (0.0017 oz) divisions. Before sampling, the suspension shall be thoroughly mixed to assure suspension of all particles, which could have settled. A 100 mL (3.40 oz) sample of the suspension shall be taken and allowed to settle for 30 minutes. The settling volume should be between 0.1 mL (0.0034 oz) and 0.25 mL (0.0085 oz) in a 100 mL (3.40 oz) sample.

   3. Wet magnetic particles may be suspended in a low viscosity oil or conditioned water.

   4. The oil shall have the following characteristics:

      • Low viscosity not to exceed 50 met (5.0 cSt) at any temperature at which the vehicle is to be used.

      • Low inherent fluorescence and be non-reactive.

   5. The conditioning agents used in the conditioned water shall have the following characteristics:

      • Impart good wetting characteristics and good dispersion.

      • Minimize foaming and be non-corrosive.

      • Low viscosity shall not exceed a maximum viscosity of 50 mSt (5.0 cSt) at 38° C (100° F).

      • Non-fluorescent, non-reactive, and odorless.

      • Alkalinity shall not exceed a pH of 10.5.

3. Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least 4.5 kg (10 lb).

Procedure

1. Insure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and any other contaminants.

2. Apply the magnetic field using the yoke against the surface in the area to be inspected.

3. For case hardened and ground surfaces:

   • Sensitivity required to locate the grinding cracks. Inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Due to the increased sensitivity resulting while the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used.

4. Visually inspect for indications of discontinuities using the proper illumination.

5. Record the size and shape of any discontinuities found.