The Swing Cylinder Line Relief Valves Need To Be Replaced On Certain 428B, 428C, 438B 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 must be administered as soon as possible. When reporting the repair, use "PI3974" as the Part Number, "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description Code. Exception: If the repair is done after failure, use "PI3974" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

Completion Date

Termination Date

Problem

The swing cylinder line relief valves need to be replaced on certain 428B, 428C, 438B and 438C Backhoe Loaders. The swing cylinder relief valves need to be replaced, and the cylinder piston bolts/nuts need to be tightened. This is necessary to achieve the expected life from the line relief valves and insure that the piston is retained to the rod. On some machines the piston bolts/nuts have already been tightened to the higher torque. Cylinders with the higher torque will have an 'x' marked on the rod eye. See Illustration 1.

Affected Product
Model & Identification Number

428B (7EJ8653-9446)

428C (8RN1-631, 8RN634, 8RN635, 8RN637-644, 8RN646-654, 8RN656-663, 8RN666-671, 8RN674-684, 8RN686-693 2CR1-1034 , 2CR1076-1080, 2CR1106, 2CR1107, 2CR1118, 2CR1119, 2CR1133-1135, 2CR1141, 2CR1184-1186, 2CR1189, 2CR1207-1226, 2CR1229-1233, 2CR1266-1281, 2CR1295-1302, 2CR1341-1343, 2CR1347-1349, 2CR1351, 2CR1408, 2CR1409, 2CR1421, 2CR1427, 2CR1428, 2CR1440-1442, 2CR1446, 2CR1447, 2CR1450-1453, 2CR1455, 2CR1457-1463, 2CR1466, 2CR1472-1482, 2CR1484, 2CR1491, 2CR1492, 2CR1505-1512, 2CR1527, 2CR1528, 2CR1533-1536, 2CR1541-1543, 2CR1548, 2CR1551, 2CR1567)

438B (3KK3635-3814)

438C (9KN1-358 1JR1-407 2DR1-592 , 2DR605-607, 2DR631, 2DR640 1TR1-517 , 1TR543, 1TR547)

Parts Needed

1 - 8C9160 Seal Assembly (if needed)

1 - 6E5649 Washer

1 - 6J2797 Ring - Wear (if needed)

1 - 2K6830 Ring - Back-Up

1 - 9X4611 Seal-O-Ring

2 - 1401148 Valve Group

NOTE: Each dealer main store may order up to 2 swing cylinders to be used when circumstances do not allow rework on site.

Action Required

See the attached procedure.

Owner Notification

U.S. and Canadian owners will receive the attached Owner Notification.

Service Claim Allowances

NOTE: This is an 8-hour job.

NOTE: U.S. and Canadian Dealers Only - Eligible dealers may enter a Type 2 SIMS Report.

Parts Disposition

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

NOTE: MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.

Attach.

(1-Owner Notification)

(2-Rework Procedure)

Copy Of Owner Notification For U.S. And Canadian Owners

Rework Procedure

Part I - Tightening the Piston

1. Look for an "x" on the rod eye of the swing cylinder. If the "x" is there, the cylinders do not need rework and go to Part 2.

2. Remove the 1166858 and 1166861 Swing Cylinder from machine.

3. Remove the 6E5651 Head from each cylinder group.

4. Tighten the 8J9992 Nut to 1300 ± 130 N·m (965 ± 95 ft-lbs).

5. Install 6E5651 Head with clean grease with new seals (and piston seals if needed) and torque to 600 ± 130 N·m (445 ± 95 ft-lbs.).

6. Stamp the rod eye with an "x" as shown in the Illustration 1 for identification purposes.

7. Bend the 6E5649 Washer into the slot on the cylinder assembly and one slot on the head as shown in detail A of Illustration 1.

Illustration 1

Part II - Replacing the Swing Cylinder Relief

1. Remove both direct acting relief valves from the swing section and install the new 1401148 Direct Acting Relief Valves, tightening to 70 ± 7 N·m (52 ± 5 ft-lbs). See Illustration 2.

Illustration 2

Part III - Clean Hydraulic System After Updating Swing System

1. After swing cylinders are reinstalled, and new relief valves installed, slowly cycle swing cylinders each direction 10-15 times to remove air.

NOTE: Cylinders must be operated slowly at first or piston seals can be damaged by air/oil travelling across the seals. This effect is called dieseling, and can cut grooves in the seal and wear band.

2. Return boom and stick to transport position and use the transport lock to hold the boom. With the engine at high idle, warm up the hydraulic oil by activating the boom down function for 60 seconds. Then operate each hydraulic circuit (bucket, swing, lift, etc.) to fill cylinders with warm oil. Repeat warming of hydraulic oil until all cylinders are warm (approximately 140 degrees F or 60 degrees C).

3. With engine at high idle, operate each cylinder 5-10 times so oil will be flushed back through the hydraulic filter. Repeat for approximately 30 minutes.

4. Take an SOS sample of the hydraulic oil. System is clean if ISO codes are below 21/16. If ISO codes are higher, repeat steps 3 and 4.