Inspection of the Coupling Assembly for 3524 Engines {3279} Caterpillar

Caterpillar Products

All 3500 Engines

Introduction

© 2019 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.

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.

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, you must 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.

Summary

This guide applies to both 180-2915 Coupling As. and 0R-3681 Coupling As.

Replace All Springs, Hubs, and Fasteners at Each Rebuild

All springs, hub plates, and fasteners are to be replaced at each engine overhaul. The coupling should be inspected when accessed and the below guidelines followed.

Caterpillar does not recommend reusing any of the remaining internal coupling components including the hub barrel, spacers, collar, and cages more than three times.

Service Letters and Technical Information Bulletins

Tooling and Equipment

Replacement Parts

Consult the applicable Parts Identification manual for your engine.

Visual Inspection

Hub Barrel

The hub barrel will first show wear on the outer flange where there is contact with the spring cages, The hub barrel should be checked for wear on this flange and spline area as well. Also check the hub barrel may only be used if there is no noticeable wear on the flange and the part is free of cracks.

Illustration 3	g03674889
Area indicated that by the arrow of the outer flange must be checked for noticeable wear.

Illustration 4	g03674913
Noticeable wear on the outer flange

DO NOT USE AGAIN

New Hub Plates at Rebuild

Dealers choosing to rebuild existing couplers with new shot peened hub plates must take the following actions after sub assembly:

1. Locate the coupling assembly part number.

   The part number is typically on the exposed area of the hub barrel.

2. Permanently mark out or etch over the existing "00" or "01" which follow the part number.

3. Stamp a new "SP" near the part number.

The "SP" mark should be visible on the outer assembly without the need of additional disassembly. The unique marking serves as visual confirmation that the coupling assembly contains the latest hub plates and is available for installation.

Coupling Assemblies for Caterpillar

As of 01 May 2014, all 3524 engine coupling assemblies manufactured by Caterpillar for parts distribution contain two new hub plates. The required "SP" marking will be present and should be located prior to use.

Reuse Exceptions

If a coupling assembly has to be removed from service prior to achieving one full life cycle, the hub plates could be considered for reuse providing the plates meet the following criteria:

• The events associated with the premature removal of the coupling are not related to the coupling system in any way.

• The coupling hub plates have not exceeded 5,000 total hours of engine run time.

• At tear down, if any internal component of the coupling assembly is damaged, the hub plates cannot be reused regardless of hours, including all 26 springs (spring are never to be reused).

• After tear down, the hub plates must pass non-destructive magnaflux inspection to identify surface damage that might be difficult to locate during visual inspection. Refer to "Crack Detection Methods" for more instructions.

After passing the selection criteria, the hub plates can be considered reusable for one new life cycle. Caterpillar recommends that Dealers properly document any reuse exception activity for future tracking purposes.

Hub Plates

The coupling assembly includes two hub plates that need to be inspected for cracks and wear. Use the magnaflux method to inspect for cracks in the hub. Replace any hub plate that has a crack or excessive wear at the spring contact area.

Illustration 5	g03674919
Indicated area requires inspection for cracks. Replace the hub plate if a crack is detected.

Illustration 6	g03674958
Indicated area requires inspection for excessive wear. Illustration 6 is an example of a hub plate that has excessive wear.

DO NOT USE AGAIN

Illustration 7	g03674968
Small amount of wear on spring contact area.

USE AGAIN

Cove Plates

There are two cove plates in the coupling assembly that needs to be inspected for wear. Replace any cove plate that has excessive wear or a wear step that can be felt.

Illustration 8	g03674976
The areas indicated by (A) are areas of the cove plate that need to be inspected for excessive wear.

Illustration 9	g03675025
Excessive wear on cove plate contact area.

DO NOT USE AGAIN

Spring Cages

There are four spring cages in the coupling assembly that must be inspected for cracks and wear. Use the magnaflux method to inspect for cracks in the spring cages. Replace the spring cages if cracks or excessive wear is detected

Illustration 10	g03675060
Indicated that areas must be check for cracks. Replace the spring cage if a crack is detected.

Illustration 11	g03675074
Indicated areas are to be inspected for wear. This particular spring cage has excessive wear.

DO NOT USE AGAIN

Illustration 12	g03675093
Excessive amount of wear on spring contact area.

DO NOT USE AGAIN

Illustration 13	g03675098
Small amount of wear on spring contact area.

USE AGAIN

Crack Detection Methods

Crack detection methods or Non-Destructive Testing (NDT) are utilized for examining components for cracks without damaging the component. Visual inspection (VT), Liquid Penetrant Testing (PT), Magnetic Particle Inspection (MT), Ultrasonic Testing (UT), Radiographic Testing (RT) and Eddy-Current Testing (ET) are recommended methods. There may be more than one acceptable crack detection method for the inspection of a given part, though the liquid penetrant is the most versatile. For example, the liquid penetrant method can be used when inspecting smooth machined components such as shafts, gear teeth, and splines, but using the Wet Magnetic Particle Inspection is more accurate. Refer to Table 3 for advantages and disadvantages and Table 4 for standards and requirements for these NDT methods.

Visual Surface Inspection (VT)

Illustration 14	g06085008
Example of Visual Inspection Tools (A) Flashlight or adequate light source (B) Magnifying eye loupe (C) Tape measure or other measuring device (D) Inspection mirror (E) Weld size inspection gauges

Components and welds that are to be inspected using PT, MT, or UT shall first be subject to Visual Surface Inspection (VT). Visual Inspection is often the most cost-effective inspection method and requires little equipment as seen in Illustration 14. It is suggested that at a minimum personnel performing Visual Inspection are either trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. It is also suggested that personnel performing visual inspections take some type of eyesight test regularly.

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

• 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

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Illustration 15	g06107074
Typical example of pre-cleaning area.

1. Preclean inspection area. Spray on cleaner / remover 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.
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   Illustration 16	g06107081
   Typical example of applying penetrant.

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 17	g06107088
   Typical example of removing excess penetrant oil.

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 18	g06107094
   Typical example of applying developer.

4. Before using Developer, ensure that it is mixed thoroughly by shaking can. Holding can approximately 203.20 - 304.80 mm (8.00 - 12.00 inch) 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 19	g06084042
   Typical example of cracks found during a liquid penetrant testing.

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 19. Clean the area of application of the developer with solvent cleaner.

Dry Magnetic Particle Testing (MT)

Materials and Equipment Required

Illustration 20	g06085930
(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 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 (MT)

Materials and Equipment

Illustration 21	g06085937
(A) Indications shown by magnetic particle testing. (B) Typical electromagnetic yoke. (D) UV Lamp used in wet magnetic particle inspection process.

Illustration 22	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) 1.0 mL (0.034 oz) divisions, refer to Illustration 22. 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 mSt (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 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 23	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 23 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.

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 form the backsurface 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 it 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.

Eddy-Current Testing (ET)

Illustration 24	g06090873
Eddy-Current Testing

Eddy-Current Testing (ET) is a Non-Destructive Testing (NDT) method in which eddy-current flow is induced in the test object. Changes in the flow caused by variations in the specimen are reflected in to a nearby coil or coils for subsequent analysis by suitable instrumentation and techniques. Major applications of eddy-current testing are surface inspection and tubing inspections.

Radiographic Testing (RT)

Note: CAUTION: This process is dangerous. Only qualified personnel and test equipment should be appointed to perform this type of testing.

Illustration 25	g06090892
Radiographic Testing

Radiographic Testing (RT) is a Non-Destructive Testing (NDT) method in which short wavelength of electromagnetic radiation is used to penetrate materials to find hidden discontinuities such as cracks. In radiographic testing, the test object is placed between the radiation source and the film, or x-ray detector. The electromagnetic radiation will penetrate the thickness of the test object and, when all the way through, will project onto the film any indications that have been in the path of the radiation waves.