Pontiac tempest 1968 Service Manual page 120

REAR SUSPENSION
4-17
5. Replace control valve i f none of the above steps
corrects problem.
INTAKE (RESERVOIR PRESSURE 125 PSI
MINIMUM)
1. Disconnect overtravel lever from link.
2. Hold lever up in intake position until Superlifts
inflate or for a minimum of 15 seconds.
3. If Superlifts inflate and hold, proceed to Time
Delay Check.
4. If Superlifts inflate and then leak down, perform
leak test on lines and fittings and then on Superlifts.
Also check and, if necessary, replace HCV intake and
exhaust screens and O-rings. If superlifts still
do not inflate, perform leak test on valve. Repair
as indicated and proceed to Time Delay Check.
TIME D E L A Y CHECK
1. Disconnect overtravel lever from link.
2. Disconnect lines at Superlift and intake port.
3. Connect test gage to intake valve port and open
air pressure (95 psi). Move overtravel lever ap­
proximately one inch down from neutral position, as
measured from end of lever.
4. Quickly move overtravel lever upward two
inches; at the same time, begin timing number of
seconds before air starts to escape from Superlift
port. This delay should be from 6-18 second. Re­
peat check. This will check the air intake time delay.
Proceed with check to determine air exhaust time
delay.
5. Remove test gage and plug intake port with
Fill Valve.
6. Connect test gage to Superlift port and open air
pressure (95 psi). Move overtravel lever approxi­
mately one inch up from neutral position, as meas­
ured from end of lever.
7. Quickly move overtravel lever downward two
inches; at the same time, begin timing number of
seconds until air begins to escape from exhaust port.
This delay should be 6-18 seconds. Repeat check.
If either delay is not within specification, there
has either been a loss of silicone fluid or valve has
lost its adjustment due to damage or wear. Valve
must be replaced.
LEAK TEST
COMPRESSOR, RESERVOIR AND REGULATOR
1. Remove assembly intact.
2. Connect test gage to regulator. Inflate reser­
voir through service valve to 80-110 psi.
3. Route an 8" piece of rubber hose between vac­
uum and vent ports (Fig. 4-28).
4. While holding assembly in a vertical position
with reservoir end down, immerse in water until
diaphragm is just submerged. Do not submerge
completely, as water can enter around the cover
gasket. Observe for air leaks at:
Reservoir weld seam.
Reservoir to compressor O-ring. A stream of
bubbles may appear in this area and then cease. The
bubbles are caused by atmospheric air being purged
from air pockets in the second stage housing. If the
bubbles stop, there is no leak.
Fig. 4-27 Test Gauge Installed on Regulator V a l v e
Fig. 4-28 Checking Compressor, Reservoir and
Regulator for Leaks