Tuesday, December 4, 2012

769D Off-Highway Truck: Front Wheel Bearing - Adjust & Front Wheel - Align

(1) Axle
(2) Wheel
(3) Retainer
(4) Threaded holes in retainer
(5) Bolts
(6) Shim pack
(7) Bearing assembly(8) Bearing assembly

Note: Before you proceed, tap the thread holes by hand or use a wire brush on the thread holes. This will remove the thread lock compound.

Install wheel (2) and bearing assemblies (7) and (8) onto axle (1) .

Without using shim pack (6), use three bolts (5) to assemble retainer (3) to axle (1). Be sure that bolts (5) are equally spaced.

Torque three bolts (5) to 102 N·m (75 lb ft).

Rotate the wheel for two revolutions in order to seat the bearings.

Torque three bolts (5) to 136 N·m (100 lb ft).

Completely loosen the three bolts (5) in order to remove the torque.

Rotate the wheel for two revolutions.

Torque three bolts (5) to 68 N·m (50 lb ft).

Rotate the wheel for two revolutions in order to seat the bearings.

Torque three bolts (5) to 68 N·m (50 lb ft).

Rotate the wheel for two revolutions in order to seat the bearings.

Repeat Step 10 and Step 11 until the specified torque does not cause any movement of bolts (5) .

Use a depth micrometer to measure the distance from the end of axle (1) to the outer face of retainer (3). Use the two threaded holes (4) in retainer (3) for this measurement. Record the average of the measurements.Note: If the difference in the measurements at the two holes is more than 0.13 mm (0.005 inch), do not continue with the wheel bearing adjustment procedure. Remove components from axle (1). Check the axle and bearing assemblies for any interference that would prevent the correct seating of the wheel bearings. Repeat the steps until the measurements are within specifications.

Remove retainer (3). Measure the thickness of retainer (3) at the two threaded holes that were used to get the previous measurements. Record the average of the measurements.

Use the average distance from the end of axle (1) to the outer face of retainer (3). Subtract the average thickness of retainer (3) from this measurement. This is the distance from the end of axle (1) to the inner face of retainer (3) .

Install shim pack (6). In order to determine the shim pack thickness, add 0.254 mm (0.0100 inch) to the distance from Step 15.Note: Apply 9S-3263 Thread Lock to bolts (5) before final assembly.

Install 6 bolts (5). While you rotate the wheel, torque bolts (5) to 250 ± 14 N·m (184 ± 10 lb ft).

2.-Front Wheel - Align

Steering linkage
(1) Clamps on left side tie bar
(2) Clamps on right side tie bar
(B) Distance between the front tires at the back(F) Distance between the front tires at the front

Use the following procedure to adjust the front wheel alignment:

Raise the axles until the strut rods in the suspension cylinders are fully extended.

Move the wheels to a straight ahead position.

Measure the distance between the front wheels at location (F) .

Mark location (F) at each tire. Rotate the tires by 180 degrees.

Measure the distance at location (B) between the same marks.

Use Table 1 to determine the correct toe-out when the front wheels are off the ground.
Table 1
Correct Toe-Out
B = F - 50.8 mm (2.00 inch)

Table 1
Correct Toe-Out
B = F - 50.8 mm (2.00 inch)

If the difference that was found in the previous step is not correct, adjust each link assembly by the same number of turns.Note: After the adjustment has been made, the tie rods must be of equal length.

When the Toe-Out measurement is correct, tighten clamps (1) and (2) to 183 N·m (135 lb ft) and lower the front of the truck.

Note: The front wheel toe-in will be correct if the difference between distance (F) and distance (B) is properly adjusted. Also, the suspension cylinders must be properly charged and the suspension cylinders must be at the normal operating range.

MARYGAR