Figure - Buick LeSabre 1965 Service Manual

6-2
REAR AXLE
c. Limits for Fitting and Adjusting
Pinion Bearing Preload
New Bearings 20-30 inch lbs. torque
with new seal
Reused Bearings 12-20 inch lbs. torque
with new seal
Ring Gear Position 007-.009 Backlash
Ring Gear Preload
New Bearings 30-40 inch lbs. torque
at ring gear
with pinion
Reused Bearings 20-30 inch lbs. torque
at ring gear
with pinion
d. Rear Axle Gear Ratios
Gear ratios are indicated by num-
bers stamped on the bottom of the
right axle tube. See Figure 6-1.
The letters designate the axle
ratio while the number designates
the day of the year that the axle
was assembled.
e. Speedometer Gears
Speedometer gears must corre-
spond with axle ratios and tire
sizes in o r d e r to have cor-
rect speedometer and odometer
readings.
6-2 DESCRIPTION OF
REAR AXLE
The rear axle assembly is of the
semi-floating type in which the
car weight is carried on the axle
shafts through ball bearings en-
closed in the outer axle housing
tubes. The rear axle is designed
for use with an open drive line
and coil springs. Drive from the
axle housing is transmitted to
body members through two lower
and two upper control arms.
Large rubber bushings at either
end of these control arms are
designed to absorb vibration and
noise. The upper control arms
are angle mounted to also hold
the body in sidewise alignment
with the rear axle assembly. The
final drive has a hypoid type ring
gear and pinion with the center-
line of the pinion below the cen-
terline of the ring gear. See
Figure 6-2.
The drive pinion is mounted in
two tapered roller bearings which
are preloaded by a collapsible
spacer during assembly. The pin-
ion is positioned by shims located
between a shoulder on the drive
pinion and the rear bearing. The
front bearing is held in place by
a large nut.
The differential is supported in
the carrier by two tapered roller
side bearings. These are pre-
loaded by inserting shims between
the bearings and the pedestals.
The differential assembly is po-
sitioned for p r o p e r gear and
pinion backlash by varying these
shims. The ring gear is bolted
to the case. The case houses two
side g e a r s in mesh with two
pinions mounted on a pinion axle
which is anchored in the case by
a bolt. The pinions and side gears
are backed by thrust washers.
The axle shaft inner splines en-
gage the differential side gears
with a floating fit. The outer ends
are supported in the axle housing
by thrust type ball bearings which
are factory packed for the life of
the bearing and sealed on both
sides. The axle shaft oil seals
are located inboard of the bear-
ings. The bearings are secured
against shoulders on the shafts
by press fit retainer rings. Re-
tainer plates hold the bearings
against shoulders in the housing.
Wheel side thrust is taken at the
wheel bearings, so an axle shaft
may be removed simply by re-
moving the bolts holding the re-
tainer to the brake backing plate
and axle h o u s i n g flange. See
Figure 6-3.
The differential c a r r i e r is a
malleable iron casting with tubu-
lar axle housings pressed into the
sides to form a complete assem-
bly. A removable, heavy steel
cover is bolted on the rear of the
carrier to permit service of the
differential without removing the
rear axle from the car. A seal
in the front of the carrier bears
against the pinion flange. See
Figure 6-2.
Brackets welded to the tubular
axle housings and upper brackets
integral with main carrier cast-
ing, form means of attaching the
rear axle to the body. An oil feed
passage to the pinion bearings and
an oil return hole are provided
in the carrier casting to allow
lubricant to circulate.
The rear axle filler plug is loca-
ted on the right side of the car-
rier casting just ahead of and
below the axle housing.
The rear brake drum is mounted
directly against the axle flange
on hub bolts pressed through the
back of the axle flange.
6-3 REAR AXLE TROUBLE
DIAGNOSIS
a. Elimination of External
Noises
When a rear axle is suspected of
being noisy it is advisable to
make a thorough test to determine
whether the noise originates in
the tires, road surface, front
wheel bearings, engine, trans-
mission, or rear axle assembly.
Noise which originates in other
places cannot be corrected by
adjustment or replacement of
parts in the rear axle assembly.
(1) Road Noise. Some road sur-
faces, such as brick or rough