Steering Pressure Switch May Not Work Properly On Certain 785 And 789 Trucks Caterpillar

Problem

The steering pressure switch may not work properly on certain 785 and 789 Trucks. A new steering pressure switch and related parts need to be installed.

Affected Product
Model & Identification Number

NOTE: All 785 Trucks that were reworked under the August 3, 1990 Service Letter - PI1150 are to be included in 785 Trucks Group 4. The following groups are for reference only. Dealers will need to check the history folder for each of the Affected Product to determine which group is applicable.

785 Trucks Group 1

785 (8GB1-222)

785 Trucks Group 2

785 (8GB223-377)

785 Trucks Group 3

785 (8GB378-407)

785 Trucks Group 4

785 (8GB408-509(Plus 8GB1-407if applicable))

NOTE: All 789 Trucks that were reworked under the August 3, 1990 Service Letter - PI1150 are to be included in 789 Trucks Group 3. The following groups are for reference only. Dealers will need to check the history folder on each of the Affected Product to determine which group is applicable.

789 Trucks Group 1

789 (9ZC1-293)

789 Trucks Group 2

789 (9ZC294-370)

789 Trucks Group 3

789 (9ZC371-552(Plus 9ZC1-370if applicable))

Parts Needed

Dealers will need to order for this Program.

785 Group 1

4 - 3D2824 Seal

1 - 8D3508 Boss

1 - 9G3695 Plug

1 - 9G9152 Clip

2 - 3J1907 Seal

1 - 3J7354 Seal

2 - 5M2894 Washer

1 - 5M3062 Bolt

1 - 7M8485 Seal

1 - 7N7779 Socket

1 - 7N7780 Pin

1 - 7N7782 Housing

1 - 5P6029 Wire-1.3 dm

1 - 5P9617 Adapter

1 - 9S4183 Plug

1 - 9S4191 Plug

2 - 0T0573 Bolt

1 - 8T4896 Washer

1 - 6V0301 Adapter

1 - 6V9004 Elbow

1 - 6V9007 Elbow

2 - 6V9746 Seal

1 - 8W5161 Manifold

1 - 8X4281 Harness As.

1 - 8X6216 Block

1 - 8X6280 Hose As.

1 - 8X7851 Fitting-Orificed

1 - 9X8199 Switch As

2H2965 Connector (Use as required)

5H5623 Wire (Use as required)

5P6001 Tubing-Shrink (Use as required)

785 Group 2

4 - 3D2824 Seal

1 - 8D3508 Boss

1 - 9G3695 Plug

1 - 9G9152 Clip

1 - 3J1907 Seal

1 - 3J7354 Seal

2 - 0L1352 Bolt

2 - 8L8413 Strap

2 - 5M2894 Washer

1 - 5M3062 Bolt

2 - 7M8485 Seal

1 - 7N7779 Socket

1 - 7N7780 Pin

1 - 7N7782 Housing

1 - 5P6029 Wire-1.3 dm

1 - 5P9617 Adapter

1 - 9S4183 Plug

1 - 8T4149 Elbow

1 - 8T4896 Washer

1 - 6V8716 Connector

1 - 6V9007 Elbow

4 - 6V9746 Seal

1 - 8X4281 Harness As.

1 - 8X5974 Manifold

2 - 8X6216 Block

1 - 8X6280 Hose As

1 - 8X7851 Fitting-Orificed

1 - 9X8199 Switch As

785 Group 3

4 - 3D2824 Seal

1 - 8D3508 Boss

1 - 9G9152 Clip

1 - 3J1907 Seal

1 - 3J7354 Seal

2 - 0L1352 Bolt

2 - 8L8413 Strap

2 - 5M2894 Washer

1 - 5M3062 Bolt

1 - 5P6029 Wire-1.3 dm

2 - 7M8485 Seal

1 - 9S4183 Plug

1 - 8T4149 Elbow

1 - 8T4896 Washer

1 - 6V8716 Connector

1 - 6V9007 Elbow

4 - 6V9746 Seal

1 - 8X5974 Manifold

2 - 8X6216 Block

1 - 8X6280 Hose As

1 - 8X7851 Fitting-Orificed

1 - 9X8199 Switch As

785 Group 4 - 8GB1-222

2 - 3D2824 Seal

1 - 7M8485 Seal

1 - 6V0301 Adapter

1 - 6V9007 Elbow

1 - 6V9746 Seal

1 - 8X7851 Fitting

785 Group 4 - 8GB223-509

2 - 3D2824 Seal

2 - 0L1352 Bolt (or 0S1619 if required)

2 - 7M8485 Seal

1 - 6V9007 Seal

3 - 6V9746 Seal

2 - 0S1619 Bolt (in place of 0L1352 if required)

1 - 8T4149 Connector

1 - 6V8716 Connector

1 - 8X5974 Manifold

1 - 8X7851 Fitting

789 Group 1

5 - 3D2824 Seal

1 - 8D3508 Boss

1 - 9G3695 Plug

1 - 9G9152 Clip

1 - 3J1907 Seal

1 - 3J7354 Seal

1 - 4J0522 Seal

1 - 5K9090 Seal

2 - 0L1352 Bolt

2 - 8L8413 Strap

4 - 5M2894 Washer

1 - 5M3062 Bolt

2 - 7M8485 Seal

1 - 7N7779 Socket

1 - 7N7780 Pin

1 - 7N7782 Housing

1 - 5P6029 Wire-1.3 dm

1 - 5P9617 Adapter

1 - 0S1595 Bolt

1 - 9S4183 Plug

2 - 0T0573 Bolt

4 - 0T0772 Bolt

1 - 8T4149 Elbow

1 - 8T4896 Washer

1 - 6V8637 Connector

1 - 6V9004 Elbow

1 - 6V9005 Elbow

4 - 6V9746 Seal

1 - 8W5161 Manifold

1 - 8X4281 Harness As

1 - 8X5974 Manifold

2 - 8X6216 Block

1 - 8X6278 Hose As

1 - 8X6279 Hose As

1 - 8X6280 Hose As

1 - 8X7851 Fitting

1 - 9X8199 Switch As

789 Group 2

5 - 3D2824 Seal

1 - 8D3508 Boss

1 - 9G9152 Clip

1 - 3J1907 Seal

1 - 3J7354 Seal

1 - 4J0522 Seal

1 - 5K9090 Seal

2 - 0L1352 Bolt

2 - 8L8413 Strap

4 - 5M2894 Washer

1 - 5M3062 Bolt

2 - 7M8485 Seal

1 - 5P6029 Wire-1.3 dm

1 - 0S1595 Bolt

1 - 9S4183 Plug

2 - 0T0573 Bolt

4 - 0T0772 Bolt

1 - 8T4149 Elbow

1 - 8T4896 Washer

1 - 6V8637 Connector

1 - 6V9004 Elbow

1 - 6V9005 Elbow

4 - 6V9746 Seal

1 - 8W5161 Manifold

1 - 8X5974 Manifold

2 - 8X6216 Block

1 - 8X6278 Hose As

1 - 8X6279 Hose As

1 - 8X6280 Hose As

1 - 8X7851 Fitting

1 - 9X8199 Switch As

789 Group 3

2 - 3D2824 Seal

1 - 5K9090 Seal

2 - 7M8485 Seal

2 - 0S1619 Bolt

1 - 8T4149 Elbow

1 - 6V8637 Connector

1 - 6V9005 Elbow

2 - 6V9746 Seal

1 - 8X5974 Manifold

1 - 8X7851 Fitting

Action Required

Parts Stock

Remove all 3T4196 Switch Assemblies from parts stock.

Affected Product

See the attached procedures.

Owner Notification

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

Service Claim Allowances

Parts Stock

Submit one claim for all 3T4196 Switch Assemblies removed from parts stock.

Affected Product

NOTE: This is a 3-hour job.

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)

(2-785 Truck Group 1 Rework Procedure)

(3-785 Truck Group 2 & 3 Rework Procedure)

(4-785 Truck Group 4 Rework Procedure)

(5-789 Truck Group 1 & 2 Rework Procedure)

(6-789 Truck Group 3 Rework Procedure)

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

785 Truck Group 1 Rework Procedure

1. Connect the 8X4281 Harness Assembly to the 9X8199 Switch Assembly.

2. Hand tighten the connector nut to the 9X8199 switch. Insert half the 130mm of 5P6029 Lockwire through one of the holes in the connector nut (Hole A) then twist the wires together. The length of the twisted wire is adjusted to fit the application. Insert one wire to closest hold clockwise around the connector (Hole B) from the top. Twist these two wires together. Cut off extra wire leaving a " stub of wire. Bend this back towards the body of the connector. See Illustration 4.

Illustration 4

3. Set this assembly aside.

4. Disconnect the chassis harness from the steering pressure switch. See Illustration 1.

Illustration 1 - Location of Manifold and Switch

5. If the chassis harness was modified with a Sure Seal connector while implementing the February 28, 1989 Service Letter - PI1113, skip the next two steps.

6. Cut off 9D3955 Connector and install 7N7782 Housing as follows. Install 7N7780 Pin on black-201 wire and install 7N7779 Socket on gray-417 wire.

7. Insert black-201 wire in position #1, grey-417 into position #2, and 9G3695 Plug into position #3 of 7N7782 Housing.

8. If the steering pressure switch is a 3T4196 Switch Assembly as shown in Illustration 1, remove the 338129 Elbow, 3T4196 Switch Assembly, and 9S4181 Plug from the 5T4762 Valve Body Block located on frame. Do not reuse the switch. Discard the switch.

9. If the steering pressure switch is a 9W2653 Switch Assembly (See February 28, 1989 Service Letter - PI1113), remove the switch and the adapter from the 5T4762 Valve Body. Do not reuse the switch. Discard the switch. See Illustrations 1.

10. Install the 9S4191 Plug and 3J1907 Seal in the Valve body. See Illustration 1.

11. Install the 6V0301 Adapter and 7M8485 Seal on top of the 5T4762 Valve Body. See Illustration 1.

12. Install the 8X7851 Orificed Fitting and 3D2824 Seal on the adapter . See Illustration 1.

13. Install the 6V9007 Elbow and 3D2824 Seal on the 8X7851 Fitting. See Illustrations 1 and 3.

Illustration 3

14. Use a 6V9746 Seal and connect the 45° end of the 8X6280 Hose Assembly to the 6V9007 Elbow.

15. Install the 6V9004 Elbow and 3D2824 Seal on the 8W5161 Manifold.

16. Connect the other end of the 8X6280 Hose Assembly and 6V9746 Seal to the 6V9004 Elbow.

17. Install the 9S4183 Plug and 3D2824 Seal on the manifold opposite the 6V9004 Elbow.

18. Rotate the manifold so the remaining port on the manifold is up.

19. Install the 5P9617 Adapter and 3J1907 Seal in the top of the manifold. Install the 9X8199 Switch Assembly and 3J7354 Seal in the adapter.

20. Bolt the 8W5161 Manifold to the block using 2-0T0573 Bolts and 2-5M2894 Washers.

21. Position the fabricated block on the frame so that the chassis harness will reach the switch harness keeping the switch vertically up and lower than the top of the frame rail. Make sure the chassis harness is not stretched or pulled tight. In the event the chassis harness is not long enough to reach the switch harness, add 5P5623 wire to the chassis harness using 2H2965 crimp type uninsulated connectors. Before crimping the connector, slide a 45 mm piece of 5P6001 Tubing (heat shrink) over the wire. Once the connector is crimped and soldered, slide the tubing over the connector and apply heat to the tubing to seal the connector. Mark this position of the block on the frame. See Illustration 2 for approximate location.

Illustration 2 - Inside of Left Frame Approximate Position To Weld Block Controlled By The Hose and Harness Length

22. Mark another place to weld an 8D3508 boss to hold the 9G9152 Clip to keep the mated Sure Seal connectors together.

23. Remove the manifold from the block and weld both the block and boss in their marked places.

24. Bolt the 8W5161 Manifold to the block using 2-0T0573 Bolts and 2-5M2894 Washers. See Illustration 3.

25. Connect the chassis harness to the 8X4281 Harness from the 9X8199 Switch and use a 5M3062 Bolt, 8T4896 Washer, and 9G9152 Clip to attach mated Sure Seal Connectors to the boss. See Illustration 3.

26. Make sure all fittings, hoses, and clips are tight.

27. Fill steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by performing "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart".

785 Truck Group 2 & 3 Rework Procedure

1. Remove the lower manifold mounting bolts from the mounting lugs. See Illustration 1 and 2. The washers will be reused.

Illustration 1 - L.H. Side View

Illustration 2 - Inside of Left Frame Position To Weld Block & Boss

2. Drill and tap one 8X6216 Block to the dimensions shown in the illustration.

3. Remove the lower mounting lugs and weld the modified 8X6216 Block with the holes in approximately the same position as the previous lugs.

4. Weld the 8X6216 Block and 8D3508 Boss to the frame at the locations shown in Illustration 2.

NOTE: For ease of installation, the 8X6216 Block may be welded later in this procedure allowing the length of the 8X6280 Hose Assembly and chassis harness to control the position to weld the 8X6216 Block. See Illustration 1. Keep switch vertically up.

5. Disconnect the chassis harness at the steering pressure switch.

6. Group 3 only. - Disconnect the 8X4281 Harness assembly from the chassis harness and set aside for use later in the procedure.

7. Group 2 only. - If the chassis harness has a Sure Seal connector, skip the next two steps.

8. Group 2 Only - Cut off 9D3955 Connector and install 7N7782 Housing as follows. Install 7N7780 Pin on black-201 wire and install 7N7779 Socket on gray-417 wire.

9. Group 2 Only - Insert black-201 wire in position #1, grey-417 into position #2, and 9G3695 Plug into position #3 of 7N7782 Housing.

10. Connect the 8X4281 Harness Assembly to the 9X8199 Switch Assembly.

11. Hand tighten the connector nut to the 9X8199 switch. Insert half the 130mm of 5P6029 Lockwire through one of the holes in the connector nut (Hole A) then twist the wires together. The length of the twisted wire is adjusted to fit the application. Insert one wire to closest hole clockwise around the connector (Hole B) from the top. Twist these two wires together. Cut off extra wire leaving a " stub of wire. Bend this back towards the body of the connector. See Illustration 4. Set this assembly aside.

Illustration 4

12. Remove the 3T4196 Steering Pressure Switch and the 5P9617 Adapter or the 9W2653 Steering Pressure Switch from the existing manifold on the truck. On Group 3 Trucks the 5P9617 Adapter will be reused later. Do not reuse the switch. Disconnect the hoses from the existing 8W5161 Manifold and remove the connectors from the manifold. Use this manifold in the next step.

13. Bolt the 8W5161 Manifold to the 8X6216 Block using 2-0T0573 Bolts and 2-5M2894 Washers. Keep the small port up when installing. See Illustration 1.

14. Install the 9S4183 Plug and 3D2824 Seal on the manifold on side towards front of the vehicle.

15. Install the 6V8637 Connector and 3D2824 Seal on the manifold on side facing rear of the vehicle.

16. Install the 8X5974 Manifold on the modified 8X6216 Block using 2-0L1619 Bolts and 2-5M2894 Washers. Position the manifold with the small port up.

17. Install the 8X7851 Orificed Fitting and 3D2824 Seal on the top of the 8X5974 Manifold.

18. Install the 6V9007 Elbow and 3D2824 Seal on the 8X7851 Fitting.

19. Install the 8X6280 Hose Assembly from the 6V9007 Elbow to the 6V8637 Connector on the upper manifold. The end of the 8X6280 Hose assembly with the 45° end should connect to the 6V8637 Connector. Use 6V9746 Seals on each end of the hose assembly.

20. Install the 5P9617 Adapter on the top of the new 8W5161 Manifold using a 3J1907 Seal. If the adapter is being reused, make sure a new seal is used.

21. Install the 9X8199 Switch Assembly and 3J7354 Seal in the 5P9617 Adapter.

22. Install a 8T4149 Connector and 7M8485 Seal to the rear side of the 8X5974 Manifold. Then connect the pump supply hose to this connector. Use a 6V9745 Seal.

23. Install a 6V8716 Connector and 7M8485 Seal on the front side of the 8X5974 Manifold. Then connect the down stream supply hose to this connector. Use a 6V9746 Seal.

24. Connect the chassis harness to the 8X4281 Harness from the 9X8199 Switch. Use a 5M3062 Bolt, 8T4896 Washer, to attach the 9G9152 Clip for the Sure Seal connector to the boss. Make sure all fittings, hoses, and clips are tight. Secure any excess chassis harness back to back with 2-8L8413 Straps. See Illustration 3.

Illustration 3

25. Fill steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by preforming "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart".

785 Truck Group 4 Rework Procedure

NOTE: Steps 1 through 7 apply only to 8GB1-222 that are to be reworked under Group 4 Affected Product.

1. Disconnect the 8X6280 Hose Assembly at the 5T4762 Valve Body.

2. Remove the 8J8559 Adapter, 9X6639 Fitting, and 8C3324 Elbow with the seal from the 5T4762 Valve Body.

3. Install the 6V0301 Adapter and 7M8485 Seal in the 5T4762 Valve Body at the location where the 8J8559 Adapter was removed.

4. Install the 8X7851 Orificed Fitting and the 3D2824 Seal in the 6V0301 Adapter.

5. Install the 6V9007 Seal and 3D2824 Seal in the 8X7851 Fitting.

6. Use a 6V9746 Seal on the 8X6280 Hose Assembly. Connect the hose to the 6V9007 Elbow.

7. Fill steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by preforming "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart".

Illustration 1

NOTE: Steps 8 through 17 apply only to 8GB223-509 that are to be reworked under Group 4 Affected Product.

8. Drill and tap one 8X6216 Block to the dimensions shown in the illustration.

9. Remove the lower manifold mounting bolts from the mounting lugs. The washers will be reused.

10. Install the 8X5974 Manifold on the 8X6216 Block using 2-0L1619 Bolts and 2-5M2894 Washers.

11. Install the 8X7851 Orificed Fitting and 3D2824 Seal on the top of the 8X5974 Manifold.

12. Install the 6V9007 Elbow and 3D2824 Seal on the 8X7851 Fitting.

13. Disconnect the hoses from the existing 8W5161 Manifold and remove the manifold. The manifold will not be reused.

14. Use a new 6V9746 Seal on the 8X6280 Hose Assembly. Connect the hose assembly to the 6V9007 Elbow on the top of the 8X5974 Manifold.

15. Install a 8T4149 Connector and 7M8485 Seal to the rear side of the 8X5974 Manifold. Then connect the pump supply hose to this connector. Use a 6V9745 Seal.

16. Install a 6V8716 Connector and 7M8485 Seal on the front side of the 8X5974 Manifold. Then connect the down stream supply hose to this connector. Use a 6V9746 Seal.

17. Fill steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by preforming "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart".

Illustration 2

Illustration 3

789 Truck Group 1 & 2 Rework Procedure

1. Drill and tap one of the 8X6216 Blocks to the dimensions shown in the illustration. Weld the modified 8X6216 Block to the center of the plate on the frame and weld the other (not modified) 8X6216 Block and 8D3508 Boss to the frame at the locations shown in Illustration 4.

Illustration 4 Inside of R.H. Frame

NOTE: For ease of installation, the 8X6216 Block may be welded later in this procedure allowing the length of the 8X6280 Hose Assembly and chassis harness to control the position to weld the 8X6216 Block. See Illustrations 5 and 6. Keep the switch vertically up.

Illustration 5 L.H. Side View

Illustration 6

2. Disconnect the chassis harness at the steering pressure switch.

3. Group 2 Only - Disconnect the 8X4281 Harness Assembly from the chassis harness and set aside for later use in this procedure.

4. Group 1 Only - If the chassis harness has a Sure Seal connector, skip the next two steps.

5. Group 1 Only - Cut off 9D3955 Connector and install 7N7782 Housing as follows. Install 7N7780 Pin on black-201 wire and install 7N7779 Socket on gray-417 wire.

6. Group 1 Only - Insert black-201 wire in position #1, grey-417 into position #2, and 9G3695 Plug into position #3 of 7N7782 Housing.

7. Connect the 8X4281 Harness Assembly to the 9X8199 Switch Assembly.

8. Hand tighten the connector nut to the 9X8199 switch. Insert half the 130mm of 5P6029 Lockwire through one of the holes in the connector nut (Hole A) then twist the wires together. The length of the twisted wire is adjusted to fit the application. Insert one wire to closest hold clockwise around the connector (Hole B) from the top. Twist these two wires together. Cut off extra wire leaving a " stub of wire. Bend this back towards the body of the connector. See Illustration 7. Set this assembly aside.

Illustration 7

IF TRUCK HAS STEERING PRESSURE SWITCH MOUNTED TO PUMP:

A. Remove the 3T4196 Switch Assembly and 3J7354 Seal from the adapter. Do Not reuse the 3T4196 Switch Assembly. See Illustration 1.

Illustration 1 - Pump Mounted Switch

B. Remove the 3P1932 Adapter and 3K0360 Seal from the Spacer.

IF TRUCK HAS STEERING PRESSURE SWITCH MOUNTED ON THE FRAME:

A. Remove the 3T4196 and 5P9617 Adapter or the 9W2653 Steering Pressure Switch from the 8T9358 Connector. Do not reuse either of the switches. The 5P9617 Adapter will be reused later on Group 2 Trucks. See Illustration 2.

Illustration 2 - Frame Mounted Switch

B. Disconnect both ends of the 8W3180 Hose Assembly. Remove the hose assembly Remove the 6V8397 Seals from the ends of the hose.

C. Loosen the 6V9168 Nut and remove the 8T9358 Connector from the 7K4426 Plate welded to frame.

D. Remove the 7K4426 Plate from the frame if desired.

E. Remove the 6V8723 Elbow and 3K0360 Seal from the spacer.

BOTH VERSIONS OF STEERING PRESSURE SWITCH LOCATION

9. Remove the 4-1D4556 Bolts, 4-5P8244 Washers, 2-1P4578 Flanges, the 4J0522 Seal, 4V7233 Spacer, and 1P3704 Seal from the pump. The flanges and washers will be reused later. See Illustration 3.

Illustration 3

10. Disconnect the 8W3794 Hose Assembly from the pump and the check valve. Remove the 5P7466 Clip, 5P7467 Clip, 5P8112 Gromet, 9V3315 Spacer, and 340172 Bolt that secures the 8W3794 Hose Assembly to the frame.

11. Replace the 340172 Bolt with a 0S1595 Bolt.

12. Bolt the 8W5161 Manifold to the 8X6216 Block using 2- 0T0573 Bolts and 2-5M2894 Washers. Bolt the 8X5974 Manifold to the modified 8X6216 Block using 2-0L1619 Bolts and 2-5M2894 Washers. See Illustration 5. Keep the small port up on both manifolds. Remove boss currently on frame if it interferes with installation of the block. See Illustration 9.

Illustration 9 Left Side View Partial 5T1025 Lines Group - Service Brake

13. Install the 6V9005 Elbow and 7M8485 Seal on the pump side of the lower manifold. See Illustration 5.

14. Use a 5K9090 Seal. Connect one end of the 8X6278 Hose Assembly to the lower manifold.

15. Connect the other end of the 8X6278 Hose Assembly to the pump using 4-0T0772 Bolts, 4-5P8244 Washers, 2-1P4578 Flanges, and a 4J0522 Seal.

16. Install a 7M8485 Seal and 8T4149 Elbow on the check valve side of the lower manifold.

17. Use the 2-6V9746 Seals and connect the 8X6279 Hose Assembly from the lower manifold to check valve. Connect the 45° end of the Hose at the lower manifold.

18. Install the 8X7851 Orificed Fitting and 3D2824 Seal on the top of the lower manifold.

19. Install the 6V8637 Connector and 3D2824 Seal in the 8X7851 Fitting.

20. Install the 9S4183 Plug and 3D2824 Seal on the upper manifold on side towards rear of the vehicle.

21. Install the 6V9004 Elbow and 3D2824 Seal on the upper manifold on side facing front of the vechicle.

22. Use 2-6V9746 Seals and connect the 8X6280 Hose Assembly between the manifolds. Connect the 45° end of the 8X6280 Hose of the lower manifold.

23. Install a 5P9617 Adapter in the top of the upper manifold using a 3J1907 Seal. If the adapter is being reused, make sure a new seal is used.

24. Install the 9X8199 Switch Assembly and 3J7354 Seal in the adapter.

25. Connect the chassis harness to the 8X4281 Harness from the 9X8199 Switch Assembly. Use a 5M3062 Bolt and 8T4896 Washer to attach the 9G9152 Clip for the Sure Seal connector. Attach the clip to the boss. Use the same bolt to secure the rerouted brake hose in the next step. See Illustration 6.

26. Reroute front service brake hose assembly so that it is clipped to the new boss that was welded to the frame. See Illustration 9. Secure any excess chassis harness back to back with 2-8L8413 Straps.

27. Rotate clip assembled to the plate on the frame which the lower manifold is assembled to 180 degrees so that it is facing outboard relative to the centerline of the vehicle. See Illustration 8.

Illustration 8 - Partial Top Front View 5T1026 Lines Group - Brake Oil Cooler

28. If the vehicle is equipped with fire suppression, relocate the clip for the fire suppression hose assembly to the front side of the steering pressure switch manifold. See Illustration 10.

Illustration 10 - L.H. Side View Partial 8W2007 Suppression Group - Fire

29. Make sure all fittings, hoses, and clips are tight.

30. Fill the steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by preforming "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart".

789 Truck Group 3 Rework Procedure

1. Remove the lower manifold mounting bolts from the mounting block. See the illustrations. The washers will be reused.

Illustration 1

Illustration 2

2. Drill and tap the lower mounting block to the following dimensions.

A) If the frame has an 8X6216 Block welded to the center of a plate:

Mark a line 20 mm below the current holes. Extend a vertical line from one of the holes to intersect the line. Drill an 8.2 mm diameter hole 20 mm deep on the line located 10 mm toward the outside edge measured from the intersection of the lines. Drill another hole on the line 50 mm from the hole. Tap both of these holes using 16-2B THD.

B) If the frame has a one piece block welded to the frame with tapped holes in the bottom for line routing brackets:

Mark a line 15 mm above the current holes. Extend a vertical line from one of the holes to intersect the line. Drill an 8.2 mm diameter hole 20 mm deep on the line located 10 mm toward the outside edge measured from the intersection of the lines. Drill another hole on the line 50 mm from the hole. Tap both of these holes using 16-2B THD.

3. Install the 8X5974 Manifold on the block using 2-0S1619 Bolts and 2-5M2894 Washers. Position the manifold with the small port up.

4. Install the 8X7851 Orificed Fitting and 3D2824 Seal in the top of the 8X5974 Manifold.

5. Install the 6V8637 Connector and 3D2824 Seal on the 8X7851 Fitting.

6. Disconnect the hoses from the existing 8W5161 Manifold and remove the manifold. The manifold will not be reused.

7. Use a new 6V9746 Seal on the 8X6280 Hose Assembly. Connect the hose assembly to the 6V9007 Elbow on the top of the 8X5974 Manifold.

8. Install a 6V9005 Elbow and 7M8485 Seal to the pump side of the 8X5974 Manifold. Then connect the 8X6278 Hose (pump supply) to this connector. Use a 5K9090 Seal.

9. Install an 8T4149 Elbow and 7M8485 Seal to the front side of the 8X5974 Manifold. Then connect the 8X6279 Hose (manifold to steering control valve) to this elbow. Use a 6V9746 Seal.

10. Fill steering hydraulic tank to proper level, check for leaks, and test system for proper operation. Also, check steering system accumulators by preforming "Every 10 Hours or Daily" check of steering system tank described in "Operation And Maintenance Manual" under "Lubrication And Maintenance Interval Chart."