The Steering System Needs To Be Modified On Certain 793 And 793B Trucks Caterpillar

The Steering System Needs To Be Modified On Certain 793 And 793B Trucks

Usage:

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Caterpillar: Confidential Yellow

NOTE: This Program must be administered as soon as possible. When reporting the repair, use "PI1225" 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 "PI1225" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and " Z" as the SIMS Description Code.

Problem

Pressure spikes might occur in the steering system of certain 793 and 793B Trucks. These pressure spikes can cause internal damage to the compensator valve, fast and frequent cycling of the steering pump, or breakage of a hose stem within the steering lines.

Affected Product
Model & Identification Number

793 (3SJ39-56)

793B (1HL12-44)

Parts Needed

Dealers will need to order parts for this Program.

1 - 3D2824 Seal O Ring

1 - 3E7432 Elbow

8 - 3J1907 Seal

1 - 4J0522 Seal-o-ring

1 - 2P8421 Adapter

1 - 9S4191 Plug

1 - 1T0936 Plug

4 - 8T4910 Bolt

1 - 8T7876 O-ring Seal

4 - 6V8337 Bolt

8 - 6V8397 Seal

3 - 6V8636 Connector

1 - 6V8724 Elbow

1 - 6V8781 Tee

1 - 6V8926 Adapter

2 - 7X2535 Bolt

^* - 8X9627 Hose Assembly (fabricated)

^* - 8X9628 Hose Assembly (fabricated)

^* - 8X9629 Hose Assembly (fabricated)

^* - 8X9630 Hose Assembly (fabricated)

1 - 8X9631 Adapter

2 - 9X8256 Washer

1 - 1077446 Valve Group

^* - 1081546 Hose Assembly (fabricated)

1 - 1082185 Valve Group

^*The dealer is to fabricate all of the hose assemblies required. One hose assembly of each part number will be required

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 a 6-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

Steering Pump

1. Disconnect the 105-3002 Hose As. from the 6E6628 Valve Group (unloading).

2. Remove the four 6V8213 Bolts which connect 6E4238 Valve Group (compensator) and 6E6628 Valve Group (unloading valve) to the steering pump.

3. Disconnect 100-6745 Tube Assembly and remove with 6E6628 Valve Group. Also, remove all fittings at both ends of tube.

4. Inspect the 6E4238 Valve Group for internal wear to spools and/or to body. If any wear is evident, replace the valve.

5. Put the 6E4238 Valve Group (compensator) in position on the pump and install the four 6V8337 Bolts that hold it.

6. Install a 6V8781 Tee with a 3J1907 Seal in the open port of compensator valve where tube was removed.

7. Remove the plug from the top port of the pump. Install 6V8926 Adapter, 3E7432 Elbow, and 1T0936 Plug using 8T7876 Seal, 6V8397 Seal, and 3J1907 Seal.

NOTE: The 1T0936 Plug threads into the 3E7432 Elbow.

8. Connect the 8X9630 Hose Assembly to fittings in tee and in top of pump using two 6V8397 Seals.

9. Connect the 8X9629 Hose Assembly to straight end of tee using 6V8397 Seal.

Front Of Suspension Support Casting (Right)

1. On right side (9T8930 Main Relief Valve Block) remove four 8T4183 Bolts and disconnect 8X5969 Hose from 8X4886 Elbow. Install 8X9631 Adapter with a 4J0522 Seal. Connect the hose with four 8T4910 Bolts and 8T4223 Washers.

2. Into port on front of adapter, screw a 6V8724 Elbow with one 3J1907 Seal, and one 6V8397 Seal.

3. Connect one end of 8X9627 Hose Assembly to elbow.

4. Remove plug from port on left top of 9T8930 Valve Group. Install 2P8421 Adapter and 6V8724 Elbow with 3D2824 Seal, 3J1907 Seal and 6V8397 Seal. Connect straight end of 8X9628 Hose Assembly to elbow.

5. It is possible that there will be interference of new hose and elbow on top of 9T8930 Valve Group. Route the 8X6061 Hose Assembly for the rear steering accumulator to prevent interference. If the bend in this hose is directed forward and the 8C4082 Tee is turned, there will be clearance for the new hose.

6. Replace the 4T2764 Relief Valve with a 108-2185 Relief Valve.

Front Of Suspension Support Casting (Left)

1. Remove 105-3002 Hose Assembly from 7I5608 Manifold. Plug hole in manifold using 9S4191 Plug with 3J1907 Seal.

2. Install the 107-7446 Valve Group (unloading) on the existing block on front of casting, near 8X4887 Manifold using two 7X2535 Bolts and two 9X8256 Washers. Mount valve with stem up.

3. In right side of unloading valve, connect 8X9627 Hose Assembly with one 6V8636 Connector, one 3J1907 Seal, and one 6V8397 Seal.

4. In bottom of unloading valve, connect 8X9628 Hose Assembly with one 6V8636 Connector, one 3J1907 Seal, and one 6V8397 Seal.

5. In left side of unloading valve, connect 8X9629 Hose Assembly with one 6V8636 Connector, one 3J1907 Seal, and one 6V8397 Seal.

Steering Lines

1. Replace 8X7787 Hose Assembly with 108-1546 Hose Assembly. Route the hose to prevent interference with grease fittings on steering cylinder head end ballstuds. Make a bend with excess hose in this area.

Illustration 1 - Existing Pump Group