VALVE 0604929 - Caterpillar

Problem
The rear suspension cylinders may experience pressure spikes on certain D350D and D400D Articulated Trucks. Pressure spikes can cause seal failure and oil leakage.
Affected Product
Model & Identification Number
D350D ( 9RF208-461)
D400D (8TF175-627, 8TF632, 8TF635, 8TF 636, 8TF638-640, 8TF652-659, 8TF662, 8TF663)
Parts Needed
1 - 5P8245 Washer-Hard1 - 7U7735 Seal1 - 1044974 Damper1 - 1044975 Valve1 - 1045008 Seal Kit1 - 1068037 Piston Parts quantities are per cylinder. If one cylinder fails, this program should be implemented to modify all four cylinders.
Action Required
See the attached procedure.
The following tools are recommended for disassembly and assembly of the suspension cylinders.Removal of cylinder end-cap (gland)...9U7869 Wrench Group - Spanner...9U7877 Plate - Adapter
Removal of piston from the piston rod...9U5131 Wrench Assembly - Spanner
Service Claim Allowances
This is a 14-hour job to rework all four cylinders. If one cylinder fails, this program should be implemented to modify all four cylinders.
If there has been a previous repair in which the customer participated, part age will apply on that suspension cylinder(s).Retain a copy of the previous repair invoice in the dealer's records for audit purposes, and specify repair date and machine hours in the "Additional Comments" section of the warranty claim.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.(1-Rework Procedure)Rework Procedure
This program should be implemented to modify all four cylinders.
1. The 7U7198 Suspension Cylinder can be modified to reduce pressure spikes. To modify the cylinder, remove and disassemble the suspension cylinder as described in the Service Manual. When disassembing the cylinder, the rod & tube should be carefully inspected to make sure that it is not worn beyond the service limits. If either are worn to excess it is recommended that the complete cylinder be replaced by a new 2U8060 Suspension Cylinder. Refer to the guideline for reusable parts for hydraulic cylinders and rods.
2. The existing metering hole closest to the piston end of the rod is a 1.5 mm (.059") diameter with a 3 mm diameter counterbore. Use a 3 mm (.116") diameter (No. 32) drill and drill the hole to a 3 mm diameter through hole. Before drilling the chrome rod, grind a small area around the hole to ensure that no chipping of surrounding chrome occurs.
3. Replace 3B4508 Washer with 5P8245 Washer-Hard. Replace 6U3951 Damper & 7U2665 Valve with 1044974 Damper & 1044975 Valve. Replace 7U7083 Piston with 1068037 Piston. Use the seals and rings in the new 1045008 Seal Kit. When installing the new components:Apply 9S3263 Thread Lock Compound on the first 2 threads of both the piston and the rod.Tighten to a torque of 1600 200 N m (1185 150 lb ft).
Apply 9S3263 Thread Lock Compound on the threads of both the piston and the retainer screw.Tighten to a torque of 20 4 N m (15 3 lb ft).
4. Before installing the cylinders, inspect 6V5002 and 6V5003 Cylinder Bearings. Replace if necessary. If the bearings are replaced, ensure that the outer ring joint is in line with the horizontal center line to 5°5. Check