Curb Weight And Height; Ball Joint Inspection Upper Ball Joint - Pontiac FIREBIRD 1972 Service Manual

FRONT SUSPENSION 3-15
CURB WEIGHT AND HEIGHT
All suspension (front wheel) alignment checks and adjust-
ments must be made with car at curb weight and height.
Curb weight means weight of vehicle including produc-
tion options and full capacity of engine oil, fuel and coo-
lant. Tire pressures, accumulated dirt, mileage, etc. must
be considered when checking curb height. To determine
if car is at normal curb height, compare with a car of
similar mileage, body style and comparable equipment.
Before measuring curb height, be sure suspension parts are
properly lubricated. Jounce the front and rear of the car
up and down, decreasing the amount of movement until
the suspension parts are equalized.
NOTE: The dimensions shown in Section 0 are
for new cars. Cars with service miles on them
will average up to about I " less than that speci-
fied for new cars.
If curb height is out of limits, install spacers or replace
springs as necessary.
NOTE: Good judgment must be exercised
before replacing a spring from a car whose curb
height is only slightly out o f limits or, although
low, is about the same at all four locations.
Spring replacement under conditions of exces-
sive weight from undercoating, road dirt, etc.
will accomplish very little.
BALL JOINT INSPECTION
UPPER BALL JOINT
The upper ball joint used on all models is a tension type
ball joint. This ball joint is equipped with a rubber preload
cushion and therefore, does not normally display loose-
ness (Fig. 3-12). The accurate method for checking a ball
joint for excessive wear is outlined below:
Be sure front suspension has been properly lu-
bricated.
Raise front wheel and tire assembly off ground by
supporting the lower control arm with a floor jack.
Raise wheel and tire high enough so rubber rebound
bumper is not touching the upper control arm or
frame.
Examine all rubber bushings at upper and lower con-
trol arm. If split or worn, they must be replaced.
Small cracks on the rubber surface are normal with
age and do not affect bushing function.
Remove ball joint stud from steering knuckle by pry-
ing on control arm using a suitable pry bar and tap-
ping sharply on knuckle in area of ball stud.
CAP RUBBER PRELOAD
Fig. 3-12 Typical Upper Ball Joint (B Series Shown)
NOTE: Instead of using a pry bar, the PRE-
FERRED METHOD using tool J 23 742-
1
can
be used (Fig. 3-23).
5. Raise upper control arm up and try to move control
arm in and out or side to side. If there is any noticea-
ble movement, the upper control arm bushings must
be replaced.
6 . Install ball joint retaining nut on ball stud. Using a
socket and torque wrench, measure amount of torque
required to turn the ball stud in its socket.
CAUTION: I f any torque is required to rotate
the ball stud, indications are that the balljoint
is in a satisfactory condition. I f zero torque is
observed, suficient wear has taken place and
the ball joint should be replaced. In instances
where a torque wrench is nct available the ball
joint can be satisfactorily checked by attempt-
ing to rotate the ball stud by hand. Some resist-
ance should always be present.
LOWER BALL JOINT
-
B 81 F SERIES
The lower ball joint used on B & F Series is a tension type
%all joint. This ball joint is equipped with a rubber preload
cushion and, therefore, does not normally display loose-
ness (Fig. 3-12). The accurate method for checking a ball
joint for excessive wear is outlined below:
1. Raise car and support front lower control arm under
spring seat.