797F Off-Highway Truck Steering System: Front Axle - Install and Adjust, Bearing Cup Cooling and Installation Procedure & Center Arm (Steering) - Adjust

1.-Front Axle - Install and Adjust

WARNING: Personal injury or death can result from sudden suspension cylinder movement. Sudden movement, up or down, can cause the clearance above your head to change rapidly. Read all warning labels on the suspension cylinders before servicing. Do not check the oil in the suspension cylinder until all the nitrogen pressure has been released. Do not, under any condition, remove valves, cover or plugs from the cylinder unless the rod is fully retracted and all the nitrogen pressure is released.Do not stand under the machine when testing or adjusting the suspension cylinders.

Table 1

Tools Needed
Tool	Part Number	Part Description	Qty
A	132-8231	Hydraulic Pump	1
	132-8159	Hydraulic Torque Wrench Gp	1
	132-8176	Wrench Link	1

Note: Perform the following procedure while the wheel, the brake, and the suspension cylinder are in the horizontal position. Refer to the Machine Systems Disassembly and Assembly, "Wheel, Brake, and Suspension (Front) - Remove" in order to remove the components from the machine.

(1) Strut rod (2) Shims (3) Plate(4) Bolts

WARNING: Personal injury or death can result when working with the strut rod. Sudden release of the spindle from the strut rod or the snapping of a bolt when removing the plate can result in injury.Loosen all bolts one-half turn, working around the plate in a circular pattern. Perform this again and again until the torque is released for the bolts.

1. Apply 4C-5593 Anti-Seize Compound to the taper of strut rod (1) . Assemble the axle to strut rod (1) . Install plate (3) . Use three bolts (4) and washers that are spaced at 120 degree intervals in order to install plate (3) . Do not use shims (2) at this time. Torque bolts (4) to 200 ± 10 N·m (150 ± 7 lb ft).

2. Use a depth micrometer at three threaded holes in plate (3) . Measure the distance from the end of strut rod (1) to the outer face of plate (3) . Record the average of the measurements.

3. Remove bolts (4) , washers, and plate (3) . Measure the thickness of plate (3) near the bolt holes which were used to make the previous measurement. Calculate the average thickness of plate (3) .

4. Install shim pack (2) . In order to determine the shim pack thickness, subtract 9.30 ± 0.03 mm (.366 ± .001 inch) from the difference between the average measurements in Step 2 and Step 3.Note: The shim pack thickness must not be less than 1.00 mm (.039 inch).

5. Install shims (2) , plate (3) , and bolts (4) . Use Tooling (A) to torque bolts (4) to 3100 ± 350 N·m (2290 ± 260 lb ft).

2.-Bearing Cup Cooling and Installation Procedure

Note: Bearing components should be pressed into cages, wheels, or other components with the bearing components at room temperature. If this is impractical, the following guidelines should be followed in order to freeze the bearing cups.

1. Bearing components should not be frozen to temperatures lower than -54 °C (-65 °F).Note: Use caution when dry ice and alcohol are used to freeze the bearing cups. A temperature of -54 °C (-65 °F) can be reached when dry ice and alcohol are used.

2. The protective covering on the outside diameter of the bearing cup should be removed before the part is placed in the freezer.Note: If the coating or oil is not removed, the preservative becomes very stiff and the preservative becomes very sticky. This frozen coating can also cause difficulty during installation.

3. When the bearing cups that are frozen come into contact with the atmosphere, water will form on the bearing surfaces. After the bearing cup is installed, the bearing cup must be wiped dry. The bearing cup must then be oiled in order to prevent corrosion during the remaining assembly procedure.Note: Damage from corrosion can occur in a short period of time. Therefore, the bearing cups should be oiled as soon as possible after installation.

4. Bearing cups should never be left in the freezer for more than one day or for a weekend.Note: Cold temperatures can change the material. The changing of the material is a function of temperature and of time. The amount of change of the material is proportional to the amount of time for freezing the part. If the part is left in the freezer too long, the service life of the part can be reduced.

3.-Center Arm (Steering) - Adjust

Top view of steering group (1) Frame steering box(2) Center arm

View A-A of steering group (1) Frame steering box (3) Bolt (4) Bearing (5) Bearing (6) Bolt (7) Bottom plate (8) Bearing (9) Pin (10) Shims(11) Top plate

View B of steering group(C) 2 ± 0.5 mm (0.079 ± 0.02 inch)

View D-D (2) Center arm (3) Bolt(11) Top plate

View E-E (2) Center arm (6) Bolt(7) Bottom plate

1. If vertical movement of center arm (2) is detected, center arm (2) must be shimmed. Use the following procedure to correctly shim center arm (2) to frame steering box (1) .
   
   
   1. Ensure that center arm (2) is resting on the bottom of frame steering box (1) .Note: Refer to the Steering System Specifications, "Steering Linkage and Cylinder Mounting" in order to choose the correct shim pack.

2. Use the following procedure to correctly shim center arm (2) .Note: Do not reuse bolts.
   
   
   1. Install bearing (4) and bearing (8) in frame steering box (1) .
   
   
   2. Install bearing (5) in center arm (2) .Note: Refer to Illustration 2 in order to view the installation of bearing (4), bearing (8) and bearing (5) .
   
   
   3. Install plate (7) with 11 bolts (6) and hard washers. The O-ring must be installed with plate (7).Note: Make sure that center arm (2) is supported properly during the adjustment procedure.
      Note: The installation of the two plates will show the gap that must be shimmed.
   
   
   4. Install plate (10) with eight bolts (3) and hard washers. The O-ring must be installed with plate (10) .
   
   
   5. Insert as many shims (10) that will fit between the top of center arm (2) and frame steering box (1) as necessary.
   
   
   6. Tighten bolts (6) to a torque value of 55 ± 10 N·m (40.6 ± 7.4 lb ft). Tighten bolts (3) to a torque of 28 ± 7 N·m (20.7 ± 5.2 lb ft).Note: Refer to the Steering System Specifications, "Steering Linkage and Cylinder Mounting" in order to choose the correct shim pack.
   
   
   7. Remove bolts (3). Remove plate (10). Install the previously determined shims (10). Add one additional thin shim.Note: Do not use more than two thin shims in the final pack. If three thin shims are required, substitute one thick shim for the three thin shims.
   
   
   8. Install pin (9) .
   
   
   9. Install bolts (3), washers, and plate (10) .
   
   
   10. Tighten the bolts to a torque value of 28 ± 7 N·m (20.7 ± 5.2 lb ft).

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