PRATT Industries TRUSS - Wheel Bearing Adjustment and Axle Alignment

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14. Install the wheels or tires and rims. Follow the torque specifications supplied by the wheel
manufacturer.
15. Adjust the brakes. (See Brake Adjustments.)
Wheel bearing adjustment
Bearing wear can cause the adjustment of the wheel bearing to loosen.
The adjustment of used wheel bearings can be checked with a dial indicator using the following procedures:
1. Remove the hubcap and gasket.
NOTE: On oil lubricated wheel ends, put an empty container under the hubcap to receive the
leaking oil when the hubcap is removed.
2. Attach the base of the dial indicator to the end of the spindle with the stem pushing against the outer
machined face of the wheel hub.
3. Check the wheel bearing endplay by pushing in on the wheel assembly while your rotate the wheel
forward and backward until the indicator does not change. Make a note of the indicator reading.
4. Now check the endplay by pulling out on the wheel assembly while you are rotating the wheel forward
and backward until the indicator does not change. The difference between the two readings is the
wheel bearing end play.
If the wheel bearing end play is:
1. Less than .012" (.30 mm), the adjustment is acceptable.
2. Greater than .012" (.30 mm) but less than .040" (1.0 mm), the bearings can continue to be used if the
bearings are not damaged.
Adjustment procedures
1. On wheel ends with single nuts, use the following procedures:
a. Remove the hubcap and gasket.
NOTE: On oil lubricated wheel ends, put an empty container under the hubcap to receive the leaking oil
when the hubcap is removed.
b. Tighten the adjusting nut to 100 Ft.Lbs. (135 N.m) torque while rotating the wheel to check
that all the bearing surfaces are in contact.
c. Loosen the nut completely and then tighten the nut to 50 Ft. Lbs. (68 N.m) torque. Then
loosen the nut 1/8 to 1/6 turn.
d. Install the cotter pin or lock ring to lock the nut in place. Bearing endplay must be within the
limits of .001" and .005" (per TMC - RP618)