525B Wheel Skidder and 535B Wheel Skidder Power Train Caterpillar

General Information

The following procedure adjusts the differential pinion preload.

Illustration 1	g00567506
Bevel Gear and Pinion (Differential) (1) Pinion shaft. (2) Bearing cone. (3) Bearing cup. (4) Pinion housing. (5) Bearing cup. (6) Bearing cone. (7) Washer. (8) Nut. (A) Bolt circle radius.

Note: The same adjustment is used for both the front pinion assembly and for the rear pinion assembly.

1. Install bearing cups (3) and (5) in pinion housing (4) without freezing. The bearing cups must be seated against the shoulders in pinion housing (4) .

2. Press bearing cone (2) on pinion shaft (1) without heating. Bearing cone (2) must be seated against the shoulder on pinion shaft (1). Lubricate bearing cone (2) .

3. Install pinion shaft (1) in pinion housing (4). Press bearing cone (6) onto the shaft. Leave a small amount of end play. Lubricate bearing cone (6). Lubricate washer (7) and nut (8) and install washer (7) and nut (8) .

   Note: If you freeze the bearing cups, allow mating parts to reach a uniform temperature. Then use a driver or a press to reset the bearing cups. The limit for freezing the bearing cups is −29°C (−20°F). Remove any frost and wipe the bearing cups dry. Lubricate the bearing cups with SAE 30 gear oil in order to prevent rust. The oil will protect the bearing cones from rust.

   Note: If you heat the bearing cones, allow mating parts to reach a uniform temperature. Then use a driver or a press to reset the bearing cones. The limit for heating the bearing cones is a maximum of 135° C (275° F) for a maximum of four hours. After the bearing cones have cooled, lubricate the bearing cones with SAE 30 gear oil. The oil will protect the bearing cones from rust.

Pinion Rolling Torque

The pinion rolling torque can be set by using two methods.

Method 1

1. Position the assembly vertically in a holding fixture. Secure pinion (1) in a holding fixture. Tighten a bolt and a nut through an outer bolt hole in pinion housing (4) .

Show/hide table



Illustration 2	g00726709

2. Place a torque wrench on the bolt so that the torque wrench is in line with the center of pinion shaft (1) .

3. While you rotate pinion housing (4) with the torque wrench, tighten nut (8) until the torque wrench reading corresponds with the value from the following formula.

   TWR = E x L / (L + BCR)

   "TWR" is the torque wrench reading in N·m.

   "E" is the rolling torque specification for the pinion bearing preload. This is 0.9 to 1.8 N·m (8 to 16 lb in) for new bearings. The rolling torque specification for pinion bearing preload for used bearings is 0.45 to 0.9 N·m (4 to 8 lb in).

   "L" is the length of the torque wrench in meters.

   "BCR" is the bolt circle radius (A) of pinion housing (4) in meters. This is equal to 0.120 m (4.72 inch) for the front pinion housing and the rear pinion housing.

   Note: Make sure that there is zero end play of pinion shaft (1) .

4. If the pinion rolling torque exceeds the specification, back off nut (8) by 1/8 turn and reseat bearing cone (6) and washer (7) against nut (8). Measure the pinion rolling torque again.

5. When the torque that is needed in order to turn pinion (1) is correct, record the torque measurement. Peen the collar that is on nut (8) into the key slot in the pinion shaft. See Illustration 3 for the correct tooling and for the correct dimensions.

   Note: The nut may be reused if the collar is not cracked during removal or during restaking.

Illustration 3	g00103469

Dimensions for the staked nut

Dimension B ... 10 to 30°

Dimension C ... 7.5 to 8.0 mm (.30 to .32 inch)

Dimension D ... 4.7 mm (.19 inch)

Dimension E ... 2.5 mm (.10 inch)

Method 2

1. Position the assembly vertically in a holding fixture. Secure pinion housing (4) in a holding fixture. Install a bolt into the end of pinion shaft (1). The bolt should be fully seated with pinion shaft (1) .

   Note: Use a bolt that will not bottom out in the pinion shaft.

2. While you rotate pinion shaft (1) with the torque wrench, tighten nut (8) until the torque wrench reading corresponds with the value in Table 1.
   Show/hide table

   Table 1

   Pinion Rolling Torque
   	Actual Torque at the Pinion
   New Bearings	0.9 to 1.8 N·m (8 to 16 lb in)
   Used Bearings	0.45 to 0.9 N·m (4 to 8 lb in)

   Note: Make sure that there is zero end play of pinion shaft (1) .

3. If the pinion rolling torque exceeds the specification, back off nut (8) by 1/8 turn and reseat bearing cone (6) and washer (7) against nut (8). Measure the pinion rolling torque again.

4. When the torque that is needed in order to turn pinion (1) is correct, peen the collar that is on nut (8) into the key slot in the pinion shaft. Record the torque measurement. See Illustration 3 for the correct tooling and for the correct dimensions.

   Note: The nut may be reused if the collar is not cracked during removal or during restaking.