GMC 4000 Series Service Manual page 130

front axle until wheels clear floor.
Check bearing 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 will be
barely noticeable and wheel will turn freely. If
movement is excessive, adjust as follows:
FRONT WHEEL BEARING ADJUSTMENT
1. With the wheel raised and axle safely sup­
ported, remove hub cap, or hub cap closure plate
and gasket.
2. Remove cotter pin securing adjusting nut to
spindle.
3. Back off the adjusting nut, then using a
torque wrench, tighten adjusting nut to 40 foot­
pounds on F-040, F-050, and F-055 axles, and 60
foot-pounds on F-070 axle, at the same time turn
wheel in both directions to be sure all bearing
surfaces are in contact.
4. Back off adjusting nut % . to 1/3 turn, or to
the nearest cotter pin hole in spindle, or sufficient­
ly to allow the wheel to rotate freely within lim its
of 0.001M to 0.007" end play.
5. Install new cotter pin and make sure that
wheel or hub turns freely.
6. Install hub cap or hub closure plate with
new gasket, and tighten cap screw s firmly.
7. Lower wheel to floor and remove jack.
FRONT HUB A N D BEARING
REPLACEMENT
REMOVAL (Fig. 1)
1. Jack up front wheel and remove tire and
rim assembly if cast wheels are used. Remove
tire and wheel assembly if ventilated disc or Budd
type wheels are used.
2. On some trucks remove the hub cap.
NOTE: On F-040 axle hub cap is threaded into
outer end of hub. On other vehicles remove cap
screw s, lock washers, hub closure plate, and gas­
ket. Discard gasket.
3. Remove cotter pin, bearing adjusting nut,
and adjusting nut washer.
4. Pull hub and drum assembly straight off
steering knuckle spindle, using care to prevent
outer bearing from dropping on floor. Remove
outer bearing cone and roller assembly from hub.
5. Pull inner oil seal out of hub; then remove
inner bearing from hub.
6. Clean, inspect, and repair parts as neces­
sary, as directed later in this section under "Clean­
ing, Inspection, and Repair."
INSTALLATION (Fig. 1)
1. Lubricate bearings, spindle, and inside of
G M C S E R V I C E M A N U A L
hub as directed in LUBRICATION (SEC. 0) of this
manual. If seal is leather, soak in oil before in­
stalling. On all other type oil seals, coat lip of
seal with wheel bearing grease or equivalent be­
fore installing.
bore in hub with a thin layer of non-hardening sea l­
ing compound, then press seal in until seal case
seats against shoulder in hub or against inner
bearing cup. On types having spring-loaded lip-
type oil seal, seal must be installed with lip point­
ing inward.
deflector and oil shield are in place on spindle.
being careful not to damage inner oil seal.
sembly on spindle, pressing firm ly into hub with
fingers. Install adjusting nut washer and adjusting
nut.
sembly.
ation as previously directed under "Front Bearing
Adjustment." Adjust brakes as directed in BRAKES
(SEC. 5) of this manual.
CLEANING
cleaning solvent. Clean with stiff brush if neces­
sary to remove old lubricant. Blow bearings dry
with compressed air, directing air stream across
bearings. Do not spin bearings while blowing them
dry.
side of hub and wipe dry. Make sure all particles
of gasket are removed from outer end of hub, and
that all sealing compound is cleaned out of oil seal
bore in inner end of hub.
wash bearing adjusting nut and washer in cleaning
solvent and wipe dry.
INSPECTION
ped edges, and other damage. Slowly roll rollers
around cone to detect any flat or rough spots.
Replace damaged parts. If either the cone and roll­
er assembly or the cup of the roller bearings are
damaged, the complete bearing assembly must be
replaced.
stalled in hub. If cups are pitted or cracked, they
must be replaced as directed later under "Repair."
FRONT HUBS A N D BEARINGS
2. Place inner bearing in hub. Coat oil seal
3. On trucks so equipped, make sure the oil
4. Carefully install hub assembly on spindle,
5. Place outer bearing cone and roller a s­
6. Install tire and rim or tire and wheel a s­
7. Adjust bearings and complete the install­
CLEANING, INSPECTION, AND
REPAIR
1. Immerse bearing assem blies in suitable
2. Thoroughly clean all lubricant out of in­
3. Clean lubricant off steering knuckle spindle,
1. Inspect bearings for excessive wear, chip­
2. Examine bearing cups which are still in­
3. Examine brake drums for scoring or other
Sec. 3D
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