Substitution Method - Pontiac TRANS AM 1977 Service Manual

STEERING, SUSPENSION, WHEELS AND TIRES
3-2 1
STEP SEQUENCE RESULT
ADD
I F TOTAL
TOTAL REAR
REAR
r
TRZN TR G
D T ; ;
G
READINGS
r
@-4
@+
[@-
LEFT REAR
I
L
I F T O T A L
+ RIGHT REAR
0 . - 0 .
TOTAL REAR
-
-
4
FRONT READING
I
-@
REAR READING A N D A GOOD TOTAL FRONT READING. SEE CHART
NOTE:
F U L L SIZE .030 INCHl0.76 mm
INTERMEDIATE .040 INCH/1.01 mm
SMALL .050 INCHl1.27 mm
PARTLY WORN TIRES SWITCHED TO THE
1
(OR LESS)
(
OPPOSITE SIDE M A Y CAUSE ROUGHNESS
-
NO VIBRATION
BALANCE A L L TIRES
NOT BALANCED I N
*
'
a
\
PREVIOUS STEPS.
PROBLEM IS NOT WHEELS
DRIVETRAIN COMPONENTS
VIBRATION
SUBSTITUTION METHOD
STEP SEQUENCE RESULT
REPLACE THOSE THOUGHT TO
TRY TO DETERMINE WHERE 0 BE BAD (IF NOT SURE, REPLACE
VIBRATION IS COMING FROM,
&
A L L FOUR) WITH KNOWN GOOD
FRONT OR REAR TIRE AND WHEEL ASSEMBLIES
FROM A SIMILAR CAR THAT
DOES NOT VIBRATE.
NO VIBRATION
PROBLEM IS NOT WHEELS
DRIVETRAIN COMPONENTS
VIBRATION
REINSTALL ORIGINAL TIRES ONE
A T A TIME UNTIL BAD TIRE
(OR TIRES) IS FOUND
I
A N D REBALANCE
I
Fig. 3-20 Tire Diagnosis