Chevrolet 70 Series 1970, Service Manual

Page: 276 / 841

REAR SUSPENSION 4-63
REAR HUBS AND BEARINGS
DESCRIPTION
R ear hubs a r e mounted on axle housing tube
on opposed ta p e re d r o lle r b earin g s as shown in
fig u re s 2 and 3. Hubs, b ea rin g s, and o il s e a ls il ­
lu s tra te d in fig u re s 2 and 3 a r e identified with type
of r e a r axle. R efer to "P ro te ct-O -P late" in Owner
Protection Plan booklet to d eterm ine type of axle
used on a specific vehicle.
Mounting p a r ts (m ainly b ea rin g s, adjustm ent
and lock nuts, s e a ls , and sleeves) shown in fig u re s
2 ana 3 a re of p rim a ry im p ortance. Brake dru m
mounting bolts, studs, and nuts differ in type and
method of installing on v ario u s s e r ie s veh icles.
New hub oil s e a ls should be in stalle d when
serv ic in g b ea rin g s if th e re is the slig h te st ind ica­
tion of w ear o r dam age. An im p erfect sea l may
p e rm it bearin g lu b rica n t to re a c h b ra k e linings,
re su ltin g in faulty b ra k e operation and n e c e s s i­
tating p re m a tu re re p lacem en t of linings.
BEARING ADJUSTMENT CHECK
Before checking w heel b earing adjustm ent,
make su re b ra k e s a re fully re le a s e d and do not
d ra g . Jac k up axle until t ir e s c le a r floor; then
rem ove axle shafts as d ire c te d in "REAR AXLES"
(SEC. 4A).
Check bearin g end play by grasping tir e at top
and pulling back and forth , o r by using a p ry b ar
under tir e . If b ea rin g s a re p ro p e rly adjusted,
m ovem ent of brake drum in re la tio n to backing
plate o r b rake sp id e r will be b arely noticeable and
wheel will tu rn fre e ly . If m ovem ent is excessive,
adjust as d ire c te d under "Wheel Bearing A djust­
m ent" following:
WHEEL BEARING ADJUSTMENT
1. Jac k up r e a r axle and rem ove axle shaft as
d ire c te d in "REAR AXLES" (SEC. 4A).
2. On v ehicles using o uter oil sea l and o u ter
oil s e a l sleev e, rem ove the sea l fro m axle shaft
flange stud s.
3. Remove b earin g lock nut and nut lock.
4. While ro tatin g the hub and d rum assem bly
in both d ire c tio n s to se a t b ea rin g s p ro p e rly in r e ­
c e s s e s of hub, tighten the adjusting nut to 50 fo ot­
pounds torque.
5. B ack off the adjusting nut 1/4 to 1/3 tu rn to
a s s u r e 0.001" to 0.007" end play.
6. Install bearin g adjusting nut lock, re fe rrin g
to figu re 1.
a. If vehicle is equipped with type shown in
View A, fig u re 1, align flat on adjusting nut with
n e a re s t lip of nut lock. Make s u re wheel tu rn s
freely ; then in stall nut lock and lock nut. Tighten
lock nut to 100-150 foot-pounds. Bend one lip of
nut lock over one flat on each nut.
b. If vehicle is equipped with type shown in
View B, fig u re 1, align dowel pin of adjusting nut
with n e a re s t hole in lock rin g. Lock ring may be
tu rn ed on e ith e r side to fa c ilita te alignm ent of hole
with le a s t m ovem ent of adjusting nut beyond 1/4 to
1/3 tu rn . In stall lock nut and tighten to 250 to 300
foot-pounds torque.
7. A fter com pleting b earing adjustm ent, r e ­
check adju stm ent to m ake su re wheel tu rn s fre e ly .
Final bearin g adjustm ent should provide within
0.001" to 0.007" end play.
8. On veh icles using o u ter oil seal and sleeve,
in stall the se a l o ver r e a r axle shaft flange stud s.
9. In stall axle shaft as d ire c te d in "REAR
AXLES" (SEC. 4A).
Figure I —Rear Wheel Bearing Adjustment Nuts
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCKSHOP MANUAL