Reuse & Salvage Procedure for Off-Highway Truck Accumulators {0374, 0599, 0679, 0738, 4269, 4331, 5077} Caterpillar

Off-Highway Truck/Tractor

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Introduction

© 2018 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 the Numerical Part Record (NPR) on the Service Information System Website (SIS Web) for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Important Safety Information

Illustration 1	g02139237

Follow all safety warnings. Most accidents that involve product operation, maintenance, or repair are caused by failure to observe safety warnings. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. Personnel must be properly trained to perform maintenance, repair, or operate any machine. Safety precautions and warnings are provided this instruction and on Caterpillar products. These warnings should be observed before performing any procedures. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are not all inclusive.

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 in Illustration 2.

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.

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manuals. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Cat dealer for replacement manuals. Proper care is your responsibility.

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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 work tools have been lowered to the ground, and the 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.

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

Summary

This guideline will discuss general procedures and practices for accumulator honing. Always refer to the correct tool operating manual for the hone that you are using.

Honing ensures that the proper surface finish is achieved and creates the proper sealing surface for new seals. by refinishing the bore back to the correct size and roundness.

Refinishing involves the removal of scratches and/or rust that is on inside the accumulator walls. An improper surface finish will prevent new seals from providing a good seal on the bore. The accumulator may leak and unexpected performance might occur. The surface roughness needs to be within a specified range. If the surface is too rough, the seal will not last for the intended life. If the surface is too smooth, proper oil retention on the bore will be inadequate. The seal may get hot due to friction which is a cause of premature failure.

Honing gives the bore a texture that will hold oil and provides lubrication for the piston seal and the wear ring. Honing will also correct noticeable distortion in bores such as out of round, bell mouth, barrel, taper, and minor dents.

All accumulators that are honed in accordance with this guideline should meet the specifications of the manufacturer.

References

Tooling and Equipment

Note: The Tooling and Equipment in Table 3 is not an all inclusive list of Tooling required to perform every task within this document. Tooling needs may vary for the scope of work to be performed for each specific rebuild.

Standardized Parts Marking Procedure

Reference: SEBF8187Reuse and Salvage Guidelines, "Standardized Parts Marking Procedures".

The code is a Cat standard and is used to record the history of a component. The code will identify the number of rebuilds and hours at the time of each rebuild. This information is important and should be considered for any decision to reuse a component.

Ensure that the mark is not covered by a mating part. Use a metal marking pen to mark the code onto the component.

Illustration 3	g06124077
DO NOT use numbering stamp punches to mark internal components.

The procedure for marking components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. During an overhaul, the previous code of a part should never be removed.

Example 1

Illustration 4	g03842417
Typical Example

Illustration 4 shows code (1-15). The first number (1) indicates that the gear had been rebuilt once. The second number (15) indicates that there were 15,000 hours on the gear at the time of rebuild.

Example 2

Illustration 5	g03842423
Typical Example

Illustration 5 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second rebuild. The first number (2) indicates that the gear had been rebuilt twice. The second number (10) indicates that 10,000 hours accumulated on the gear between the first and second rebuild.

Note: Add the first and second rebuild hours to obtain the total number of hours for the gear in Illustration 5. In this example, the gear has a total of 22,000 hours.

Service Advisories, Service Letters, and Technical Service Bulletins

Honing Oil

Honing oil is specially formulated to perform in the demanding conditions set fourth by the hone. Some reasons for using proper honing oil include:

• Minimize galling and chatter.

• Provide lubrication to stones and guides.

• Extend the life of the hone tooling.

• Reduce operating costs.

• Increase the quality of the finished product by cooling and carrying away the honing process residue as intended.

Do not dilute the honing oil. Do not use lubricating oil, cutting oil, or water-soluble oil. Consistent results cannot be expected unless the recommended full strength honing oil is used. Use of the wrong oil or not enough oil volume can cause steel to embed in the stone. When embedding happens, the stone is bad and should be replaced.

Use the honing oil that has the proper formulation for steel tubes and viscosity.

Manually run the hone oil into the accumulator, as shown in the Tool Operating Manual. Perform this action until oil is flowing out of the open end of the accumulator into the top of the hone oil tank. Observe the diameter of hone oil as the oil falls from the accumulator. To start out with, the diameter of the hone oil stream should be about the size of a pencil or slightly larger, approximately 8-10 mm (0.31-0.39 inch). The hone oil flow should be enough to allow proper lubrication and chip removal. However, too much flow can contribute to an excessive amount of oil to be thrown off the hone head and out of the open end of the accumulator.

Note: The main ingredient in the honing oil is animal fat, which may solidify at cold temperatures. This solidification will not harm the system and the oil will dissolve once the honing oil is warm.

Oil should be filtered before pumping into the hone head. Contaminated oil is a large reason for poor hone performance. If the honing oil is contaminated, the oil will introduce more unwanted, abrasive particles into the honing system. These particles can cause scratches and gouges in the bore. The particles can become lodged between the stone or holder and the bore. A scratch can occur as the particles travel around with the hone head.

One reason customers do not purchase the correct oil is the cost. In the end, the cost of oil is less than 0.1% of the total honing process. Use the correct oil to increase the life of the hone tooling. The correct honing oil decreases the time and labor that is needed to complete the honing process.

The Caterpillar hone oil tank incorporates a roll of filter media that should be rolled to expose clean filter media every few accumulators. Once the entire roll of filter media is used, inspect and possibly change the hone oil. Check for sludge at the bottom of the tank. Use a piece of wood or steel as a dipstick to check for solids at the bottom of the tank. If necessary, completely drain and clean the tank. Fill the tank with new hone oil.

Cleaning

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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 product used to clean the components. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of cleaning agents.

The honing process creates a large quantity of abrasive particles that must be cleaned from the accumulator before the accumulator is resealed. The abrasives are either stone particles, the binder used to hold the stone particles together, guide material, or metal shavings from the bore. Abrasives can cause accelerated wear to accumulator seals and other components in the system if not properly removed from the bore.

After honing, allow the honing oil to drain from the accumulator assembly. Properly wash the accumulator assembly inside diameter using the cylinder washer available from Dealer Service Tools, or equivalent. Reference the Tool Operating Manual, NEHS0927, "Procedures for Using the Cylinder Washer Tank Group" for operating and repair instructions.

Illustration 6	g01179117
250-6597 Cylinder Washer

The cylinder washer is used to:

• Clean honing oil and metal particles from inside reconditioned components (provides quick and efficient cleaning method).

• Cleans components ranging from 101 to 343 mm (4.0 to 13.5 inch) diameter and 1.9 to 3.6 m (6 to 12 feet) in length.

• Unit can be positioned at end of manual or semi-automatic hone group (allows components to remain clamped in hone group during cleaning process).

• Washer uses an air-powered drill to rotate cleaning brushes while a pump supplies cleaning solvent to the brush head.

• Uses a disposable bag filter to capture contaminants (keeps wash solvent clean and making cleanup and disposal much easier).

• Unit is shipped with 110-volts capability, but can easily be converted to 220-volts (no additional parts are required for the conversion).

Cleaner/Degreaser contains agents that provide rust protection for up to two days, and is available in 18.95 L (5.0 US gal).

If the accumulator will not be assembled for several weeks, coat all exposed metal surfaces with clean hydraulic oil. All openings must be capped and plugged. If the accumulator will not be assembled for up to a year, Vapor Phase Corrosion Inhibitor (VCI) Oil should be used. Refer to Special Instruction, SEHS9031, "Storage Procedure for Caterpillar Products" for general storage recommendations.

The storage times given are approximate. Ambient temperature and humidity level will greatly affect the storage time. Both types of oil can be applied with a spray wand. The accumulator opening must have a protective covering after the oil is applied.

Accumulator Bore Finishing

Note: The honing process is only used to obtain the rough dimension.

1. Hone to obtain near the ID requirements, circumferential pattern acceptable, the pitch or advanced of the lay pattern must be no greater than 12.70 mm (0.500 inch) per revolution.

2. Depending on bore size, burnish to exact requirements or use a flapper wheel to obtain the surface texture.

3. If using flapper wheels, start with a 180 grit, then use 240 grit and next apply 440 grit.

4. The inside diameter of the accumulator is to be free of any flaws, scratches, cracks, burrs, or other irregularities after honing. Refer to "Crack Detection Methods" for methods of inspections.

Crack Detection Methods

There are five major crack detection methods or Non-Destructive Testing (NDT) listed in this section: Visual Surface Inspection (VT), Liquid Penetrant Testing (PT), Dry / Wet Magnetic Particle Testing (MPT), and Ultrasonic Testing (UT).

Crack detection or NDT is a method for testing components for cracks without damaging the component. VT, PT, Dry/ Wet MPT, and UT are methods recommended. There may be more than one acceptable crack detection method for the testing of a given part, although PT is the most versatile. For example, the PT method can be used when testing smooth machined components such as shafts, gear teeth, and splines, but using the Wet MPT is more accurate. Refer to Table 6 for advantages and disadvantages and Table 7 for standards and requirements for these NDT methods.

Visual Surface Inspection (VT)

Illustration 7	g06124166
Example of Visual Surface Inspection (VT) Tooling (A) Flashlight (or adequate light source) (B) Magnifying Glass (C) Tape Measure (or other measuring device) (D) Inspection Mirror

Refer to Tooling and Equipment Table 3 for part numbers.

Components and welds that are to be tested using PT, MPT, or UT shall first be subject to a Visual Surface Inspection (VT). VT is often the most cost-effective inspection method and requires little equipment as seen in Illustration 7. Personnel performing VT shall either be trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. Personnel performing VT shall take routine eye exams.

Liquid Penetrant Testing (PT)

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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.

• Penetration Oil: 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 penetrating oil indications.

• Wire Brush: Removes dirt and paint.

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

Procedure

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Illustration 8	g06261388
Typical example of pre-cleaning the testing area.

1. Preclean the area to be tested. Spray on cleaner/ remover to loosen any scale, dirt, or any oil. Wipe the area to be tested with a solvent dampened cloth to remove remaining dirt and allow the area to dry. Remove paint where there are visible cracks using paint remover or a wire brush.

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Illustration 9	g06261354
Typical example of applying penetrating oil to areas to be tested.

1. Apply penetrating oil by spraying to the entire area to be tested. Allow 10 to 15 minutes for penetrating oil to soak. After the penetrating oil has been allowed to soak, remove the excess penetrating oil with clean, dry wipe.
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   Illustration 10	g06261357
   Typical example of removing penetrating oil with a cloth.

2. The last traces of penetrating oil should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
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   Illustration 11	g06261359
   Typical example of applying the developer.

3. Before using developer, ensure that the developer is mixed thoroughly by shaking the container. Hold the container approximately 203 - 305 mm (8 - 12 inch) away from part. Apply an even, thin layer of developer over the area being tested. A few thin layers are a better application method than one thick layer.
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   Illustration 12	g06261360
   Typical example of cracks found during Liquid Penetrant Testing (PT).

4. Allow the developer to dry completely for 10 to 15 minutes before inspecting for cracks. Defects will show as red lines in white developer background, refer to Illustration 12. Clean the area of application of the developer with solvent cleaner.

Dry Magnetic Particle Testing (MPT)

Materials and Equipment Required

Refer to Tooling and Equipment Table 3 for part numbers.

Illustration 13	g06085930
(A) Indications shown by Dry Magnetic Particle Testing (MPT). (B) 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 lbs).

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. Ensure 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 Testing (MPT)

Materials and Equipment

Refer to Tooling and Equipment Table 3 for part numbers.

Illustration 14	g06085937
(A) Indications shown by Wet Magnetic Particle Testing (MPT). (B) Electromagnetic Yoke (D) Ultraviolet Lamp

Illustration 15	g06003178
Pear Shaped Centrifuge Tube

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.

   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, refer to Illustration 15. 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 5 mm²/_s (5 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 5 mm²/_s (5 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 lbs).

Procedure

1. Ensure 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.
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   Illustration 16	g03536210

3. For case hardened and ground surfaces:

   • Due to the 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. Also, due to the increased sensitivity resulting when the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used. See Illustration 16 for an example of yoke placement.

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

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

Ultrasonic Testing (UT)

Note: Crack depth cannot be accurately determined by UT, only full depth cracking can be consistently determined. For cracks that are not full depth, an indication of a partial depth cracks can be detected by an experienced technician. Refer to Table 7 for crack detection standards.

Refer to Tooling and Equipment Table 3 for part numbers.

1. Ultrasonic Testing (UT) is a method of Non-Destructive Testing (NDT) using short ultrasonic pulse waves (with frequencies from 0.1-15 MHz up to 50 MHz) to detect the thickness of the object. Ultrasonic testing consists of an ultrasound transducer connected to a diagnostic machine and passed over the object being inspected.

2. There are two methods of receiving the ultrasound waveform from the transducer: reflection and attenuation.

   1. Reflection - Ultrasonic pulses exit the transducer and travel throughout the thickness of the material. When the sound waves propagate into an object being tested, the waves return to the transducer when a discontinuity is discovered along the sonic path. These waves continue and reflect from the back surface of the material to project the thickness of the material.

   2. Attenuation - A transmitter sends ultrasound through one surface, and a separate receiver detects the amount that has reached the separate receiver on another surface after traveling through the medium. Any discontinuities or other conditions within the medium will reduce the amount of sound transmitted, revealing the presence of the imperfections.