Chevrolet 70 1969 Series, Shop Manual

Page: 179 / 913

REAR SUSPENSION 4C-40
SECTION 4C
REAR HUBS AND BEARINGS
DESCRIPTION
Rear hubs are mounted on axle housing tube
on opposed tapered roller bearings as shown in
figures 2 and 3. Hubs, bearings, and oil seals il­
lustrated in figures 2 and 3 are identified with type
of rear axle.
Mounting parts (mainly bearings, adjustment
and lock nuts, seals, and sleeves) shown in figures
2 and 3 are of primary importance. Brake drum
mounting bolts, studs, and nuts differ in type and
method of installing on various series vehicles.
New hub oil seals should be installed when
servicing bearings if there is the slightest indica­
tion of wear or damage. An imperfect seal may
permit bearing lubricant to reach brake linings,
resulting in faulty brake operation and necessi­
tating premature replacement of linings.
BEARING ADJUSTMENT CHECK
Before checking wheel bearing adjustment,
make sure brakes are fully released and do not
drag. Jack up axle until tires clear floor; then
remove axle shafts as directed in " R E A R A X L E S "
(SEC. 4A).
Check bearing end play by grasping tire at top
and pulling back and forth, or by using a pry bar
under tire. If bearings are properly adjusted,
movement of brake drum in relation to backing
plate or brake spider will be barely noticeable and
wheel will turn freely. If movement is excessive,
adjust as directed under "Wheel Bearing Adjust­
ment” following:
WHEEL BEARING ADJUSTMENT
1. Jack up rear axle and remove axle shaft as
directed in "R E A R A X L E S " (SEC. 4A).
2. On vehicles using outer oil seal and outer
oil seal sleeve, remove the seal from axle shaft
flange studs.
3. Remove bearing lock nut and nut lock.
4. While rotating the hub and drum assembly
in both directions to seat bearings properly in re­
cesses of hub, tighten the adjusting nut to 50 foot­
pounds torque.
5. Back off the adjusting nut 1/4 to 1/3 turn.
6. Install bearing adjusting nut lock, referring
to figure 1.
a. If vehicle is equipped with type shown in
View A, figure 1, tighten adjusting nut with T-
handle wrench 12" long each side. Tighten until
hand wrench tight; this should result in approxi­
mately 50 foot-pounds torque. Loosen nut at least
45 degrees until flat on nut aligns with tab of nut
lock. Install lock nut, and tighten against nut lock,
and adjusting nut, until torque of 100-150 foot­
pounds is reached. Bend one tab of nut lock over
one flat of each nut to secure nuts in place.
b. If vehicle is equipped with type shown in
View B, figure 1, align dowel pin of adjusting nut
with nearest hole in lock ring. Lock ring may be
turned on either side to facilitate alignment of
hole with least movement of adjusting nut beyond
45 degrees. Install lock nut and tighten to 200 to
300 foot-pounds torque.
7. After completing bearing adjustment, re­
check adjustment to make sure wheel turns freely.
Final bearing adjustment should provide within
0.001" to 0.007" end play.
8. On vehicles using outer oil seal and sleeve,
install the seal over rear axle shaft flange studs.
9. Install axle shaft as directed in "R E A R
A X L E S " (SEC. 4A).
Figure 1— Rear Wheel Bearing Adjustment Nuts
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L