Pontiac FIREBIRD 1972 Service Manual page 260

FRONT SUSPENSION
3-9
TROUBLE DIAGNOSIS (Continued)
TYPICAL FRONT SHOCK
BOllOM
MOUNT
\
DOWN
TYPICAL REAR SHOCK
SHOCK
---LA
Fig. 3-5 Position for Purging Air from Shock
-
a noise, such as a grunt or squeal, after comp-
leting one full stroke in both directions
-
a clicking type noise at fast reversal
-
fluid leakage
5. To check for a loose piston, completely extend
shock to full rebound; then exert an extra hard
pull. If a give is felt, a loose piston is indicated and
shock should be replaced.
II. Gas Filled Cell
The reservoirs of gas-filled cell shocks are smooth,
compared to the spiral goove type. The cell takes the
place of air in the reservoir. Thus, aeration or foam-
ing of the fluid is eliminated, as air and fluid cannot
mix.
Due to this feature, these shocks should be bench
checked in an inverted position (top end down). If,
when stroked, a lag is notices, it means the gas-filled
cell has been ruptured, and the shock should be re-
placed. If no lag is noticed, the remainder of the
bench check is the same as given in the Spiral Groove
Reservoir, Section I, Bench Check Procedure.
The gas-filled cell feature is used in the service re-
placement shocks.
Ill. Superlift
These shocks contain an air chamber like the spiral
groove reservoir type, and must have the air purged
from the working chamber. See Section I, Spiral
Groove ~eservoir. After air has been purged from
-
-
shock, proceed as follows:
a. Clamp lower shock mounting ring in vise in verti-
cal position with larger diameter tube at the top.
'
b. Pump unit by hand. Smooth resistance should be
felt throughout the length of the stroke. Since the
units are normally pressurized, the sound of air
bubbles or a gurgling noise is normal.
c. The remainder of the bench check is the same as
given in the Spiral Groove Reservoir, Section I,
Bench Check Procedure.