Product Support Program For Increasing The Brake Modulation On Certain 950F Wheel Loaders Caterpillar

Product Support Program For Increasing The Brake Modulation On Certain 950F Wheel Loaders

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Caterpillar: Confidential Yellow

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 "PS4761" 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: Some of the Affected Product fall into more than one group. Do all applicable portions of this Service Letter at the same time.

Termination Date

June 30, 1993

Problem

Group 1

Brake modulation occurs over a small range in the movement of the brake pedal on 950F Wheel Loaders listed in this group. Operators may complain that the brakes activate "too quickly" when the brake pedal is applied.

Group 2

The 950F Wheel Loaders listed in this group may experience braking when the transmission neutralizer pedal is being depressed.

Affected Product
Model & Identification Number

Group 1

950F (7ZF1-739; 6YG1-894; 4DJ1-596; 05A9940)

Group 2

950F (7ZF1-544, 7ZF546-578, 7ZF580-583, 7ZF585-590, 7ZF592-595, 7ZF597-650, 7ZF652-652, 7ZF654-658, 7ZF670-702, 7ZF704-704, 7ZF705-705, 7ZF707-715, 7ZF717-717, 7ZF718-718, 7ZF720-808, 7ZF810-812, 7ZF814-816, 7ZF818-818, 7ZF819-819, 7ZF821-824, 7ZF826-846, 7ZF848-855, 7ZF859-859, 7ZF862-862; 6YG1-1409; 4DJ1-Up; 05A9940)

Parts Needed

Group 1

2 - 4D2287 Valve Assembly

Group 2

2 - 4B2047 Nut

2 - 4B4274 Washer

1 - 9G5127 Breather

1 - 3J1907 Seal

3 - 5K9241 Fitting

4 - 8L8413 Cable Strap

1 - 8T3285 Adapter

1 - 9U3715 Harness

1 - 3V0037 Hose Assembly

2 - 6V6867 Screw

1 - 9X0378 Switch Assembly

1 - 9X9482 Valve Group

Action Required

Group 1

Replace the two existing brake modulation valves (8V5172), located beneath the brake pedal and the brake neutralizer pedal, with two new 4D2287 Valves.

Group 2

Install a 9X9482 Valve Group and a 9X0378 Switch Assembly as described in the attached procedure.

Service Claim Allowances

Parts Disposition

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

Attach.(1-Rework Procedure)

Rework Procedure

1. Remove the front plug (Item 1) (Illustration 1).

2. Remove the neutralizer line (Item 2) (Illustration 1).

3. Remove the neutralizer line adapter and elbow (Item 3) (Illustration 1). This adapter and elbow will not be reused.

4. Install the plug (Item 1), that was removed in Step 1, in the opening from which the neutralizer line adapter and elbow (Item 3) were removed in Step 3 (Illustration 1).

NOTE: After this step, the plug is referred to as Item 4 in Illustration 2.

5. Install the 8T3285 Adapter (Item 5) (Illustration 2) in the opening from which the plug was removed in Step 1.

6. Install a 3J1907 O-Ring Seal over the threaded end of the 9X0378 Pressure Switch Assembly (Item 6) and then install the switch in the 8T3285 Adapter (Item 5) (Illustration 2).

7. Remove the valve plug (Item 7) (Illustration 1) and install the 5K9241 Fitting (Item 8) (Illustration 2) in its place. Position the fitting so the open end is facing to the front.

NOTE: The plug removed from the valve in this step will not be reused.

8. Tighten the fitting (Item 9) (Illustration 3) at the end of the 9X9482 Valve Group (Item 10) (Illustration 3).

9. Install the 9G5127 Breather (Item 11) on the 9X9482 Valve Group (Item 10) (Illustration 2).

10. Install two 5K9241 Fittings (Item 12) (Illustration 3) in the valve group (one on each side). Install the fittings in the positions shown in Illustration 3.

11. Drill holes in the bottom of the cab floor to mount the valve group as shown in Illustration 2. Use the mounting flanges of the valve group as a template being careful not to drill through the floor mat in the cab. Remove any burrs that occur.

12. Put the valve group in position on the bottom of the cab. Use two 9X2498 Screws, 4B2047 Nuts, and 4B4274 Washers (Item 13) (Illustration 3) to hold the valve. Connect the black ground wire of the 9U3715 Harness A (Item 14) to the bolt (Item 13) closest to the modulation valve (Illustration 2).

13. Connect one end of the 9U3715 Harness (Item 14) to the wire leading from the valve group. Connect the other end of the harness to the 9X0378 Switch Assembly (Item 6) (Illustration 2).

14. Connect the green wire on the harness (Item 15) to the green wire on the brake switch (located near the hand metering unit).

15. Connect the neutralizer line (Item 16) (Illustration 2) to the fitting that is turned to a 30 degree angle on the valve group.

16. Connect one end of the 3V0037 Hose Assembly (Item 17) to the fitting on the valve group. Connect the other end to the fitting on the brake modulation valve (Illustration 2).

17. Tie the ends of the harnes and wires with the 8L8413 Ties (Item 18) (Illustration 3).

Illustration 1