Pontiac FIREBIRD 1972 Service Manual page 289

REAR SUSPENSION
4-3
TROUBLE DIAGNOSIS (Continued)
AUTOMATIC LEVEL CONTROL RAISES CAR TO PROPER HEIGHT BUT LEAKS D O W N
Follow steps below. If first step is O.K., proceed down list until problem
is corrected.
CAUSE
a. Lines or fitting leaking.
b. Control valve exhaust leaking.
c. Superlifts leaking.
d. Control valve leaking.
CORRECTION
a. Leak test lines and fitting from the control
valve to Superlifts and the crossover lines. Repair if
leaking.
b. Perform on car control valve test and repair if
leaking.
c. Perform Superlift leak test and replace if
leaking.
d. Perform off car control valve test and repair
as needed.
AUTOMATIC LEVEL CONTROL ONLY PARTIALLY RAISES CAR WHEN LOADED
Follow steps below. If first step is O.K., proceed down list until problem
is corrected.
CAUSE
a. Excessive load over axle.
b. Control valve setting incorrect.
c. Low pressure in system.
CORRECTION
a. Distribute load, shift forward if practical and
caution owner of car.
b. Perform trim height adjustment.
c. Perform compressor output test and repair as
needed.
AUTOMATIC LEVEL CONTROL RAISES CAR TOO HIGH W H E N CAR IS UNLOADED
Follow steps below. If first step is O K . , proceed down list until problem
is corrected.
CAUSE
a. External damage or breakage.
b. Control valve setting incorrect.
c. Defective control valve.
CORRECTION
a. Inspect lines, linkage, control valve, and Superlifts.
Repair or replace damaged parts.
b. Perform trim height adjustment.
c. Perform off car control valve test and repair
as needed.
AUTOMATIC LEVEL CONTROL RAISES CAR WHEN LOADED BUT LEAKS D O W N ONLY WHEN
CAR I S DRIVEN
CAUSE
a. Time delay mechanism malfunctioning.
CORRECTION
a. Test and repair time delay mechanism.