Pontiac FIREBIRD 1972 Service Manual page 1248

WHEELS AND TIRES 10-1 1
cylinder to bring the level down to 1/4-in. below the
lowest edge of the filler opening. Replace the cover
but do not clamp it into place.
5. Balance wheels.
6. After balancing, pump up brakes until the pedal re-
turns to normal height.
7. Re-fill master cylinder (Fig. 5-6).
NOTE: When balancing rear wheels on the car,
always check to see if car is equipped with Safe-
T- Track differential. Never balance Safe- T-
Track-equipped car with onc wheel on ground
as car may move when engine is started and
transmission is in drive gear.
WARNING: WHEN BALANCING TIRES ON THE
CAR, FOLLOW THE EQUIPMENT MANUFAC-
TURER'S INSTRUCTIONS CAREFULLY. ON
CARS WHICH DO NOT HAVE SAFE-T-TRACK,
DRlVE WHEEL SPIN SHOULD BE LIMITED TO
35 MPH AS INDICATED ON THE SPEEDOME-
TER. THlS LIMIT IS NECESSARY BECAUSE THE
SPEEDOMETER ONLY INDICATES ONE-HALF
OF THE ACTUAL WHEEL SPEED WHEN ONE
DRlVE WHEEL IS SPINNING AND THE OTHER
DRlVE WHEEL IS STOPPED. UNLESS CARE IS
TAKEN IN LIMITING DRlVE WHEEL SPIN, THE
SPINNING WHEEL CAN REACH EXCESSIVE
SPEEDS, RESULTING IN POSSIBLE TIRE DISIN-
TEGRATION OR DIFFERENTIAL FAILURE,
WHICH COULD CAUSE PERSONAL INJURY OR
EXTENSIVE VEHICLE DAMAGE.
ON CARS WHICH DO HAVE SAFE-T-TRACK,
DRlVE WHEEL PIN SHOULD BE LIMITED TO 70
MPH. ON SUCH CARS, DO NOT ATTEMPT TO
BALANCE A TIRE ON A DRlVE WHEEL WITH
THE OTHER DRlVE WHEEL ON THE GROUND
SINCE THE CAR MAY DRlVE THROUGH THlS
WHEEL.
If car is equipped with Safe-T-Track rear axle, the balanc-
ing of the rear wheels should be performed as follows:
a. Raise and block the rear of the vehicle with both
wheels off the floor.
b. Remove one wheel.
c. Reinstall two (2) lug nuts and tighten securely to
retain the brake drum.
d. Proceed with balancing operation on the remain-
ing wheel using engine power to spin the wheel.
e. When proper balance has been achieved on first
wheel, reinstall the second wheel and balance in
the same manner.
8. When balancing rear wheels on the car, remember
that: with one wheel on the ground, speedometer
speed is one-half (1/2) rear wheel speed. With both
wheels off the ground, speedometer speed is the same
as rear wheel speed.
INSTALLING WHEELS
CAUTION: See Caution on page 1 of this Sec-
tion regarding the fasteners referred to below.
Wheel lug nuts must be gradually and alternately torqued
to 75 lb. ft. for B Series or 70 lb. ft. for A, F, X or G Series.
Improper tightening will distort the wheel or the brake
drum.
SPECIFICATIONS
WHEELS
........................................................
F Series 6" and 7"
Material
....................................................................
Steel
..........................................................
X Series 5" and 6"
Type
....................
Drop Center
-
with flat safety hump
Diameter
....................................................
B Series 15"
TORQUE
........................................................
G and X Series 14"
..........................................
A and FSeries 14" and 15"
B Series Wheel to Drum Nut
Width
............................................................
B Series 6" Front and Rear
..........................................
75 Lb. Ft.
G Series 7"
A, F, X and G Series Wheel to Drum Nut
........................................................
A Series 5", 6" and 7" Front and Rear
..........................................
70 Lb. Ft.
....................................................