GMC 1982 Light Duty Truck Service Manual page 348

3C-6 FRONT SUSPENSION
a.
Ball joints and steering linkage need lubric ation
h.
Shock a b so r b e r loose or bushings w o rn
c Worn c o n tr o l arm bushings
.
d.
Worn tie rod e nds
e. Worn or loose wheel bearings
f. Loose sta b ili/e r bar
Loose wheel nuts
g.
h. Spring im pro pe rly p ositioned
i. Loose suspension bo lts
a. Tire and wheel ou t o f balance
h.
Tire and wheel ou t o f ro und
Blister or b u m p on tire
c.
d. Im p ro p er shock a b so rb er action
a.
U n dcrinflated or overin flated tires
b.
I m p ro p e r toe-in
c Wheels ou t o f balance
.
d. Hard Driving
0. Over loaded vehicle
a.
Toe-in in correct
b. Excessive speed on tu rn s
c.
Tires im p ro p e rly inflated
d.
Suspensio n arm b e n t o r tw isted
a. F ro n t shock a bso rbers defective
b.
Worn ball jo in t s
c. Wheel bearings in corre ctly a dju ste d or worn
d.
Wheel and tire o u t o f balance
c. Excessive tire or wheel r u n o u t
Bounce Test
This is only a comparison type test to help locate the
suspected shock or noise condition before proceeding.
Test each front and rear shock by bouncing each corner
of the vehicle. This can usually be done by lifting up and
pushing down on the end of the bumper near each corner of
the vehicle until maximum movement up and down is
reached. Then let go of bumper and observe if the up and
N O IS E IN F R O N T E N D
Probable Cause
W H E E L T R A M P
E X C E S S IV E O R U N E V E N T I R E W E A R
S C U F F E D T IR E S
C U P P E D T IR E S
Fig. 3C-5~Front Suspension Diagnosis Chart
Probable Remedy
a. Lubricate at r e c o m m e n d e d intervals
b. T ighten bolts a n d /o r replace bushings
c.
Replace bushings
d.
Replace tie rod ends
e.
Adjust or replace wheel bearings
f.
T ig hten all stabili/er bar a tta c h m e n ts
g.
T ighten the wheel nuts to p ro p e r to rq u e
h.
Reposition
j.
T o rq u e to specifications or replace
a.
Balance wheels
b.
Replace tire
c. Replace tire
d.
Replace sh ock absorber
a. Inflate tire to pro pe r r e c o m m e n d e d pressure
b.
Adjust toe-in
c. Balance wheels
d. Instruct driver
e.
Instruct driver
a. Adjust toe-in to specifications
b.
Advise driver
c.
Inflate tires to p roper r e c o m m e n d e d pressure
d. Replace arm
a.
Replace shock absorbers
b. Replace ball joints
c.
Adjust or replace wheel bearings
d. Balance wheel and tire
e.
C o m p e n s a te for runout
B
down motion stops very quickly. If up and down motion
continues longer at one corner when compared to opposite
corner (example, both front shocks), the one having the
longer up and down motion may be suspect. Do Not
compare front to rear. If complaint is noise, this test should
help to locate the suspected area.