Product Support Program For Reworking The Lock Valve On Certain 428C And 438C Backhoe Loaders Caterpillar

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4084" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

Termination Date

Problem

Backhoe Loaders with the loader lock valve option exhibit problems of jerky, uneven movement and noisy operation. This problem applies equally to machines supplied ex-factory with the option and those fitted with the field installed kit 1353501.

Affected Product
Model & Identification Number

428C (8RN1-1004, 2CR1-2415 )

438C (9KN1-368, 2DR1-729 , 1JR1-409 , 1TR1-615 )

Parts Needed

3 - 3J1907 Seal-O-Ring

2 - 3J7354 Seal-O-Ring

4 - 4J5477 Seal-O-Ring

1 - 5K9090 Seal-O-Ring

1 - 7M8485 Seal-O-Ring

2 - 5P7982 Elbow-O-Ring

1 - 8T1674 Tee

4 - 6V0405 Seal-Bonded

6 - 6V8397 Seal-O-Ring

2 - 6V8647 Connector

2 - 6V9849 Elbow-Swivel

1 - 7X3163 Adapter

1 - 7X3406 Cross

2 - 1446300 Valve

2 - 1448311 Adapter

2 - 1450227 Velocity Fuse

1 - 1451037 Hose Assembly

1 - 1451038 Hose Assembly

1 - 1451039 Hose Assembly

Action Required

See the attached rework procedure.

Service Claim Allowances

NOTE: This is a 5-hour job.

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Attach.

(1-Rework Procedure)

Rework Procedure

1. Remove the lift cylinder lock valves. Install two new 1446300 Valves.

2. Install a 5P7982 Elbow with a 3J1907 Seal in the port marked "F" of each valve.

3. Install a 1450227 Velocity Fuse in each elbow, using two 6V0405 Seals.

4. Connect the two velocity fuses using 1448311 Adapters, 6V8397 Seals and a 1451039 Hose. Route the hose with tubes from the Loader valve to the lift lock valves, and secure with tie wraps.

5. Install a 6V9849 Elbow and 6V8647 Connector using two 4J5477 and a 3J7354 Seal in the port marked "D" of each lock valve.

6. Disconnect HMU tank hose at the oil filter, remove the 1173232 Hose from the 8T6356 Tee. Remove the 8T6356 Tee from the filter.

7. Install an 8T1674 Tee using a 7M8485 and a 5K9090 Seal, connect the 1173232 Hose to the tee. Add a 7X3163 Adapter using a 3J1907 Seal. Add a 7X3406 Cross-union using four 6V8397 Seals.

8. Connect the HMU tank hose to the cross-union arm facing right.Connect the 1451037 Hose from the bottom arm of the cross-union to the right lock valve (6V9849 Elbow).Connect 1451038 Hose from the left arm of the cross-union to the left lock valve (6V9849 Elbow). See Illustration 1.

9. Remove the tread plate from the fuel tank and add a cut out (see Illustration 1).

Illustration 1