Pontiac FIREBIRD 1972 Service Manual page 293

REAR SUSPENSION 4-7
TROUBLE DIAGNOSIS (Continued)
8. If air escapes around edge of cover plate, the gasket 2. Hold lever up in intake position for maximum Super-
must be replaced.
lift inflation and release.
9. Remove control valve from water. Actuate over-
3. Leak check all connections with a soap and water
travel lever to expel any water from unit.
solution.
10. Shut off air pressure and remove line from Superlift
Dart.
LINES AND FITTINGS
-
LEAK TEST
SUPERLIFT
-
LEAK TEST
1. Disconnect overtravel lever from link. See SHOCK ABSORBER.
GENERAL DESCRIPTION
COIL SPRING
A four link rear suspension is used on all models except
B Series station wagons, commercial chassis and F
&
X
Series. The axle housing is connected to the frame by two
upper and two lower control arms with rubber pivot bush-
ings at each end of the control arm. Upper and lower
control arm bushings are the same size but are not inter-
changeable in some applications as different rubber
specifications are required for particular locations. The
control arms maintain the geometrical relationships of the
rear axle with the frame, oppose torque reaction on accel-
eration and braking and provide for optimum handling
characteristics (Fig. 4-4).
Two coil springs support the weight of the car in the rear
suspension. They are retained between seats in the frame
and brackets welded to each axle housing tube (Fig. 4-5).
A rubber insulator is used to isolate the coil spring upper
end from the frame seat and the lower end sits directly on
the axle tube mounted bracket.
Sealed shock absorbers are mounted between a bracket
welded to each axle housing tube and the upper spring
seat, with the top inclined toward the center of the car.
The shock absorbers are externally the same for all mod-
els, but vary in hydraulic control to provide a well-con-
trolled but soft ride.
A steel stabilizer shaft is used to improve side roll stability
on A Series with the GTO or G T option. The one-piece
shaft attaches to the lower control arms and is positioned
directly under the differential axle housing. The shaft will
support the weight of the car when a two-post axle engag-
ing hoist is used for lifting.
Rubber bumpers are mounted near the outer ends of the
axle housing and at the center of the frame cross member
to prevent metal-to-metal contact during compression
travel or bottoming of the suspension.
LEAF SPRING
The rear suspension (Fig. 4-6) on B Series station wagons,
Fig. 4-4 Typical Coil Spring Rear Suspension
Fig. 4-5 Typical Coil Spring Lower Seat