Modes of Failure for Quick Disconnect Connectors {0618, 5057, 6129} Caterpillar

Modes of Failure for Quick Disconnect Connectors {0618, 5057, 6129}

Usage:

Mini Hydraulic Excavator: All
Compact Wheel Loader: All
Multi Terrain Loader: All
Skid Steer Loader: All
Work Tool:: A13 (S/N: ACY1-UP); A14B (S/N: MRS1-UP); A19 (S/N: ADA1-UP); A19B (S/N: SMR1-UP); A26 (S/N: AKF1-UP); A26B (S/N: LLS1-UP); A7 (S/N: 7BZ1-UP); A7B (S/N: JMT1-UP); BA18 (S/N: ACE1-UP; AZN1-UP); BH27 (S/N: B2H1-UP); BH30 (S/N: B3H1-UP); BH30 W (S/N: B3W1-UP); BP15 (S/N: ACT1-UP); BP15B (S/N: MPB1-UP); BP18 (S/N: ADH1-UP); CV16 (S/N: ACH1-UP); CV18 (S/N: AAM1-UP); CV18B (S/N: RCA1-UP); LR15 (S/N: ADF1-UP); LR15B (S/N: EFS1-UP); LR18 (S/N: ADP1-UP); LR18B (S/N: DAS1-UP); LT13 (S/N: AAS1-UP); LT13B (S/N: CHZ1-UP); LT18 (S/N: ABZ1-UP); LT18B (S/N: LDA1-UP); PC203 (S/N: PCB1-UP); PC204 (S/N: RDG1-UP); PC205 (S/N: RBG1-UP); PC206 (S/N: DDG1-UP); PC210 (S/N: GDR1-UP); PC3 (S/N: ABW1-UP); PC4 (S/N: ACC1-UP); PC6 (S/N: AKS1-UP); PC9 (S/N: ALC1-UP); SG16 (S/N: ALJ1-UP); SG16B (S/N: MAP1-UP); SG18 (S/N: AMG1-UP); SG18B (S/N: SGL1-UP); SR17 (S/N: SBA1-UP); SR18 (S/N: SBB1-UP); SR21 (S/N: SBC1-UP); SW45 (S/N: WWS1-UP); SW60 (S/N: WLS1-UP); T15 (S/N: ABL1-UP); T15B (S/N: SLW1-UP); T9 (S/N: ABC1-UP); T9B (S/N: JAJ1-UP)

Introduction

This Special Instruction is created in order to provide guidance for determining the failure mode of the quick disconnect connectors. The information should be used in order to determine if the failure is a defect in material or workmanship that is covered by the warranty. The information should also be used in order to determine if the failure is caused by misuse. Misuse is not covered by the warranty.

Misuse causes the majority of the failures for the quick disconnect connector. One common cause of failure is the entry of debris. Occasionally, the work tool lines are connected with the machine before the debris is properly removed. Make sure that the couplings are clean before the couplings are connected. Another common cause of failure is the use of force in order to disconnect the auxiliary lines and failure to use the proper procedure for the release of hydraulic pressure.

Operation Of A Quick Disconnect Connector

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Illustration 1	g01278017
Typical Quick Disconnect Connector (A) Female coupling (B) Lock ball (C) Notch (D) Male coupling (E) Valve (F) Balls (G) Inner sleeve (H) Fixed stem

When the two couplings are pushed together, inner sleeve (G) in the female coupling is pushed away from fixed stem (H). At the same time, the fixed stem in the female coupling unseats valve (E) in the male coupling. This opens a flow path between the two couplings. Balls (F) in the female coupling engage with a groove in the male coupling. The engagement locks the two couplings together.

Notch (C) in the locking collar on the female coupling is aligned with lock ball (B) in the body as the two couplings are connected. After the connection, the locking collar should be rotated so that the ball and the notch are out of alignment. This prevents the couplings from inadvertently releasing during operation.

Essential Precautions For The Proper Operation Of Quick Disconnect Connectors

The following precautions must be observed for the proper operation of the quick disconnect connectors:

Relieve hydraulic pressure on the machine before attempting to disconnect the couplings. The couplings may stick after the hydraulic pressure is released. Slide the locking collar and tap the connector with a soft faced hammer. The sticking is normally due to debris or previous misuse.
Maintain the hydraulic system by preventing dirt from entering. Change the filters at the recommended intervals. Contaminated oil can damage internal seals.
Make sure that the mating faces of the couplings are clean before the couplings are connected.
Install plastic caps or plugs when the couplings are disconnected in order to protect the mating faces.
Make sure that the notch in the locking collar is aligned with the lock ball before the locking collar is pulled back in order to disconnect the couplings.
Do not strike the coupling with a hammer or a similar tool in order to disconnect the couplings. Do not strike the coupling with a hammer or a similar tool for any reason. This will damage the coupling.
Connect and disconnect the new couplings several times in order to break in the seals. The connectors may stick if the seals are not broken in.
Do not damage the coupling faces. Damage such as burrs and scratches can damage the seals, which can cause leaks. Damage to the faces can also impede the connection and disconnection of the couplings.
Use the correctly sized wrench on the hexagon body of the coupling. Do not use a tool that has serrated jaws on the plain section of the coupling.
Keep the balls on the inside of the female coupling lubricated with 186-1528 Silicone Lubricant or an appropriate silicon grease.
Do not attempt to connect the couplings if one of the couplings is damaged. The use of a damaged coupling will damage the seals in the mating connector.
Correctly stow the couplings when the couplings are not used. Stow the couplings in a way that will prevent damage from crushing or other external influences. Stow the couplings in a way that will prevent dirt accumulation.
Do not use force in order to rotate the locking collar on the female coupling when you disconnect the coupling. Rotation of the locking collar can cause the lock ball to jam under the locking collar.
Do not disassemble the couplings. Serviceable parts are not available. Replace damaged couplings with new Caterpillar couplings.
Use the correct part numbers only. Do not attempt to mix the couplings.

Couplers That Are Damaged By Misuse

The information that follows has examples of the couplers that are damaged by misuse. Damage by misuse is not covered by the warranty.

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Illustration 2	g01277786
Damage Of The Seal On The Stem

Refer to Illustration 2. The stem seal has been damaged. A portion of the seal is missing. This has been caused by contamination or misuse.

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Illustration 3	g01277788
Damage On The Face Of The Stem

Refer to Illustration 3. The front face of the central stem has been damaged from being struck repeatedly with a tool. This was probably in an attempt to release trapped pressure. The central stem is hard mounted within the female coupling. Striking with a tool causes distortion of the stem, which leads to operational difficulties. A seal is located on the underside of the face. This type of misuse will cause damage to the seal.

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Illustration 4	g01277792
Distorted Coupler

Refer to Illustration 4. The locking collar on the female coupling has been distorted. The locking collar will not move. Marks on the edge of the coupling show that the distortion was caused by hammering the locking collar into the lock ball. This was possibly an attempt to release the male coupling without aligning the lock ball with the notch in the locking collar. The locking collar has been forced over the lock ball in an attempt to align the lock ball with the notch.

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Illustration 5	g01277794
Dislodged Seal On The Stem

Refer to Illustration 5. The seal on the stem has been dislodged during the connection of the couplings. The coupling has been connected with force without releasing the pressure. Leakage will occur after the coupling is disconnected.

Cleaning the Quick Disconnect Connectors

Periodic cleaning of the female half of the quick disconnect connectors can minimize the occurrences of sticking. Cleaning will remove dirt and contaminants that tend to accumulate inside the connector. The recommended procedure for cleaning the connector is provided below.

Remove the quick disconnect connector. Use the proper wrench in order to prevent damage to the quick disconnect connector.

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Illustration 6	g00893366

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Illustration 7	g00893368

Use a screwdriver and push back the outer sleeve. See Illustration 6.
Note: When the outer sleeve is pushed back, the inner sleeve becomes partially exposed and the operating sleeve moves forward. The internal parts of the quick disconnect connector are now accessible for cleaning. See Illustration 7.

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Illustration 8	g00893370

Wash the quick disconnect connector by placing the quick disconnect connector in a shallow container that contains a recommended cleaning fluid. Agitate the quick disconnect connector in the cleaning solution. Continue to push back the outer sleeve so that the cleaning fluid can wash the internal parts. Repeat washing until the quick disconnect connector is clean. See Illustration 8.
Note: Use the appropriate protective equipment when you work with cleaning solutions.

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Illustration 9	g00893372

Remove the quick disconnect connector from the cleaning solution. Close the quick disconnect connector by aligning the locking ball and the notch and pushing back the operating sleeve. See Illustration 9.