Usage:
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 "PS4796" 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.
NOTE: This Revised Service Letter replaces the May 12, 1999 Service Letter. Changes have been made to the Affected Product.
NOTE: This Revised Service Letter replaces the May 12, 1999 (Revised June 1999) Service Letter. Changes have been made to the Service Claim Allowances.
Termination Date
May 31, 2000Problem
The brake pedal pivot pin needs to be reworked on certain IT18F, IT24F and IT28F Toolcarriers and 918F, 924F and 928F Wheel Loaders. Corrosion at the pivot pin area and dirt build-up under the heel of the brake pedal can prevent the pedal from returning to zero position after it is released following a brake application. The resulting residual brake pressure leads to elevated axle oil temperatures and reduced brake disc life.
Affected Product
Model & Identification Number
918F (3TJ1-Up, 2CK1-Up, 5DL1-Up)
IT18F (6ZF1-Up, 5EJ1-Up)
924F (5NN1-1444, 4YN1-1751, 6MN1-994)
IT24F (4NN1-1285, 6KN1-324)
928F (8AK1-Up, 2XL1-Up)
IT28F (3CL1-Up, 1JL1-Up)
Parts Needed
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. Move machine to level ground and activate the parking brake.
2. Connect the steering frame lock link.
3. Release the pressure in the hydraulic system as follows:
a. Shut off the engine.
b. Move the control levers through their full travel strokes. This will relieve any pressure that may be present in the pilot system.
c. Slowly loosen the fill cap on the hydraulic oil tank to release the pressure.
d. Tighten the fill cap on the hydraulic oil tank.
e. The pressure in the hydraulic system has now been released.
4. Put identification on all tubes, lines and hoses for installation purposes and cap all lines to prevent loss of hydraulic oil.
5. Disconnect the brake lines and wiring harness from the brake valve under the operator station.
6. Remove both the right and left brake pedal assemblies.
7. Remove the brake valve, stoplight and neutralizer switch from the left brake pedal.
8. Remove the pedal from each base assembly and shorten the heel of each pedal by 19 mm to eliminate possibility of dirt and debris buildup under pedal preventing full brake release. See Illustration 1 for cutting instructions.
9. Using 1612304 Kit, install new pedal pivot pin and bushings in new 1611427 Right Pedal Base, using previously modified pedal.
10. Using 1515595 Kit, install new pedal pivot pin and bushings in new 1611426 Left Pedal Base, using previously modified pedal.
11. Reassemble stoplight switch and neutralizer switch in pedal base using new switch cam and O-ring on shaft. Note the 1056118 Neutralizer Switch is located toward the center of the pedal assembly with the 1056117 Stop Light Switch, located at the outside of the pedal assembly.
12. Reassemble brake valve to left pedal assembly.
13. Reassemble both right, left pedal assemblies and connecting 9U0773 Shaft to operator station.
14. Reassemble lines to brake valve and reconnect wiring harness. Disconnect the steering frame lock link. Bleed brakes and test operation. Replace hydraulic oil as necessary.
15. An additional hour has been allowed so the service technician can have the operator check machine and adjust neutralizer switch to operating conditions and operator preference. This process is necessary to eliminate slope "rollback" and "harshness and jerky operation" when the transmission engages and disengages. "Rollback" and "harshness and jerky operation" encourage operator to lockout transmission neutralizer causing "drive through brakes" conditions which reduces service brake life. The "Brake System Specification" module in the various service manuals describes an adjustment procedure for the neutralizer switch assembly. This procedure can also be found in Service Magazine article published 22-Jan-1996.
Illustration 1.