Trailer Axle

d. Wheel Bearings Replacement (fig. 4-6). Drain

b. The trailer axle uses a positive bearing

as much oil from the unit as possible by removing plug

adjustment feature. When the wheel and parts are

in side of hub cap and rotate the hole to the bottom.

assembled into position, the proper bearing adjustment

Replace plug when all oil is out.

is obtained automatically by tightening the retaining nuts

against the shoulder on the axle spindle. The bearing

(1) Loosen and remove the six cap screws

adjustment will range from .005 inches .007 inches

and lockwashers securing the hub cap.

loose. Both the inner (adjusting) and outer (jam ) nuts

are tightened to 250-300 ft.-lb. The adjustment can in

(2) Remove hub cap and its gasket.

time become looser, especially when the bearing wear is

(3) Remove bearing jam nut,

pierced

accelerated by contaminated lubricant.

lockwasher, and wheel bearing adjusting nut.

c. The after-service adjustment condition can be

(4) Remove hub and outer and inner bearings

checked by means of a dial indicator.

with brake drum from axle spindle.

(1) Loosen and remove the six capscrews

CAUTION

and lockwashers fastening hub cap. Drain oil first.

When removing hub the brake

drum will come with it. Do not let

(2) Remove hub cap and gasket.

brake drum drag across brake

(3) Attach indicator base to end of the axle

shoes or drop down on axle

spindle and the stem should bear against the outer

spindle.

machined face of the wheel hub. (A magnetic base

indicator is easier and faster to mount).

(5) Remove bearings from hub.

(4) Watch the indicator while pushing inward

(6) Remove seal from hub.

on the wheel assembly and roll it back and forth until the

indicator stops changing. Make note of this reading.

(7) Remove wiper from spindle journal.

(5) Pull outward and roll the wheel assembly

(8) Clean hub cavity and spindle journal

until the indicator again stops changing. Make note of

removing all nicks and burrs.

this reading.

(9) Install new wiper.

See

this

(6) The difference between the two readings

paragraph.

taken in (4) and (5) above is the adjustment condition.

(10) Install new oil seal in hub. (See f of this

(7) If the difference is .040 inches loose or

paragraph.)

greater, the bearings should be replaced even though

(11) Install hub with the new oil seal and

they may appear satisfactory.

bearings on axle spindle.

(8) If the difference is greater than .012

(12) Install wheel bearing adjustment nut and

inches loose but less than .040 inches loose see h. of

tighten with a torque wrench to 250-300 ft.-lb., while

this paragraph.

rotating hub back and forth.

(13) Install pierced locking washer.

(14) Install outer jam nut and tighten with a

torque wrench to 250-300 ft.-lb.

(15) Install hub cap. (See g of this paragraph

(16) Fill hub with recommended oil to level

indicated on hub cap. Rotate wheel and re-check oil

level.

4-16