Reuse and Salvage Guideline for Cracks in Hydraulic Cylinder Rod Assemblies {0599, 0738, 5102, 7562} Caterpillar

Mining Truck

794 AC (S/N: HRT1-UP)

Off-Highway Truck/Tractor

794 AC (S/N: MN51-UP)

796 (S/N: HRZ1-UP)

MT4400D AC (S/N: MH41-UP)

Introduction

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Caterpillar 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 guideline enables dealers and dealer customers to benefit from cost reductions made possible through an established parts reusability and salvage program. Every effort has been made to provide the most current information known to Caterpillar Inc. Since the company makes ongoing product changes and product improvements, this guideline must be used with the latest technical information. Using the latest technical information available from Caterpillar ensures that such changes and improvements are incorporated where applicable.

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 not 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.

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 the procedure is safe for you and for other people to use. Ensure that the product will not be damaged or 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 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.

Safety

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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.

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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 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.

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Rerodding, straightening, or welding any steering cylinder rod, bowl cylinder rod, or front suspension cylinder rod could result in injury or death. If any of these rods are broken or cracked, the rods must be replaced with a REMAN rod or a new rod. These rods can be ground and plated with chrome if the recommended Caterpillar process that is identified in this document is used.

Summary

Illustration 3	g06359290
Piston Seal Groove Cracks

Some 431-5865 Rod As assembly tubes may exhibit cracking in the corners of the piston seal groove. These cracks require repair before the part may be placed back into service. This Reuse & Salvage Guideline will provide one method of salvage.

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 scope of work to be performed for each specific rebuild.

Welding Specifications

Crack Repair

1. If a defect has already been found, proceed to Step 3.
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   Illustration 4	g06355577
   Piston Seal Groove Location

2. Inspect the piston seal groove for cracks in the corners. Refer to Illustration 4. Use VT/PT or VT/MPT for this purpose. If cracks are found proceed to Step 3.

3. Machine off the piston portion of the tube. Turn the outside diameter to 274.00 + 0.00 -0.05 mm (10.79 + 0.00 -0.002 inch), for a length of 136.0 + 5.0 - 0.00 mm (5.354 + 0.197 - 0.00 inch) from the end.

4. Re-inspect the tube to ensure the cracks have been machined off. If cracks remain, the tube is not usable and must be scrapped.
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   Illustration 5	g06355625

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   Table 5

   Dimension	Ring 1	Ring 2
   A	33.25 ± 0.25 mm (1.31 ± 0.01 inch)	69.75 ± 0.25 mm (2.75 ± 0.01 inch)
   B	304.75 ± 0.25 mm (12.0 ± 0.01 inch)	304.75 ± 0.25 mm (12.0 ± 0.01 inch)
   C	274.0 ± 0.05 mm (10.79 ± 0.002 inch)	274.0 ± 0.05 mm (10.79 ± 0.002 inch)
   D	15° ± 0.50°	15° ± 0.50°

5. Machine two rings from a low carbon steel such as cold drawn SAE1026. Refer to Illustration 5 for ring sizes.
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   Illustration 6	g06359301
   Weld Locations and Sizes

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   Table 6

   Ring 1	A	136.65 ± 0.25 mm (5.38 ± 0.01 inch)
   Ring 2	B	11.8 ± 0.89 mm (0.46 ± 0.035 inch)

6. Slide the two rings over the machined outside diameter. Ring 1 should go on first, then Ring 2. The chamfered faces should be positioned to the inside, facing each other. The square end of each ring should face toward either end of the tube.

7. Position Ring 2 11.8 ± 0.89 mm (0.465 ± 0.035 inch) from the end of the tube. Clamp the ring to hold it in position and secure in place with a 12 mm (0.472 inch) fillet weld at the left edge. Refer to Illustration 6. Follow Reuse and Salvage Guideline , SEBD0512, "Caterpillar Service Welding Guide".

8. Position Ring 1 136.65 ± 0.25 mm (5.38 ± 0.01 inch) from the end of the tube. Clamp the ring to hold it in position. This will create a bevel groove weld joint with a root opening. Use a 16.00 mm (0.63 inch) weld with full penetration to secure the rings to the tube. Refer to Illustration 6. Follow Reuse and Salvage Guideline , SEBD0512, "Caterpillar Service Welding Guide".
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   Illustration 7	g06369143
   New Piston Machine Features (AE) Perpendicularity (AF) Concentricity

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   Table 7

   Location	Dimension
   A	254.038 ± 0.038 mm (10.0015 ± 0.0015 inch)
   B	279.3175 ± 0.0445 mm (10.9967 ± 0.00175 inch)(1) 279.3745 ± 0.0255 mm (10.99897 ± 0.001 inch)(2)
   C	135.125 ± 0.25 mm (5.32 ± 0.01 inch)
   D	88.9 ± 0.25 mm (3.50 ± 0.01 inch)
   E	65.02 ± 0.25 mm (2.56 ± 0.01 inch)
   F	7.925 mm (0.312 inch)
   G	38.42 ± 0.0635 mm (1.51 ± 0.0025 inch)
   H	9.64 ± 0.0635 mm (0.38 ± 0.0025 inch)
   J	3.2 µm (0.126 µin) Surface Texture
   K	38.42 ± 0.0635 mm (1.51 ± 0.0025 inch)
   L	9.65 mm (0.38 inch)
   M	1.524 mm (0.06 inch) x 45°
   N	R 0.381 mm (0.015 inch)
   P	15°
   Q	1.6 µm (0.063 µin) Surface Texture
   R	Ø 302.768 ± 0.05 mm (11.9 ± 0.002 inch)
   S	Ø 264.236 ± 0.025 mm (10.403 ± 0.001 inch)
   T	4.83 mm (0.19 inch)
   U	16.0 ± 0.25 mm (0.63 ± 0.01 inch)
   V	44.45 mm (1.75 inch)
   W	R 4.85 ± 0.05 mm (0.191 ± 0.002 inch)
   X	0.127 mm (0.005 inch)
   Y	0.051 mm (0.00201 inch)
   AA	15°
   AB	Ø 282.13 ± 0.0635 mm (11.11 ± 0.0025 inch)
   AC	Ø 278.51 ± 0.127 mm (10.965 ± 0.005 inch)
   AD	Ø 298.30 ± 0.05 mm (11.744 ± 0.002 inch)
   Notes:	All radii to be 1.5 ± 0.5 mm (0.06 ± 0.02 inch), including in the seal groove corners.

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   (1)	Before Plating
   (2)	After Plating

9. Machine the outside of the new piston to the dimensions shown in Illustration 7. Pay attention to the surface finish on the sealing groove.

   Note: The new piston seal groove shall have a radius of 1.5 ± 0.5 mm (0.059 ± 0.0197 inch) in the corners.

10. Finish hone the bore to a surface finish of Ra = 0.1 - 0.3 microns and a bore size of 254.0 + 0.08 -0.00 mm (1.00 + 0.003 - 0.00 inch). Refer to Reuse and Salvage Guideline , REHS2689, "Hydraulic Cylinder Honing".

11. Re-inspect all machined dimensions.

12. Perform any other needed repairs to the tube such as chrome plating or polishing the outside diameter. Refer to Reuse and Salvage Guideline, SEBF8072, "Inspection and Salvage of Hydraulic Cylinder Components" for more salvage procedures.

Acceptance Criteria

Visual Surface Inspection (VT)

Illustration 8	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, or MPT 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 8. 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.

• Penetrating 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 9	g06103795
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 10	g06103803
   Typical example of applying penetrating oil to areas to be tested.

2. Apply penetrant by spraying to the entire area to be tested. Allow 10 to 15 minutes for penetrant 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 11	g06103816
   Typical example of removing penetrating oil with a cloth.

3. 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 12	g06103820
   Typical example of applying the developer.

4. Before using developer, ensure that the developer is mixed thoroughly by shaking the container. Hold the container approximately 203 - 305 mm (8.0 - 12.0 inch) away from the testing area. Apply an even, thin layer of developer over the testing area. A few thin layers are a better application method than one thick layer.
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   Illustration 13	g06084042
   Typical example of cracks found during Liquid Penetrant Testing (PT).

5. Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as red lines in white developer background, refer to Illustration 13. 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 14	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 15	g06085937
(A) Indications shown by Wet Magnetic Particle Testing (MPT). (B) Electromagnetic Yoke (D) Ultraviolet Lamp

Illustration 16	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 16. 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 17	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 17 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.