Hummer H1 (2002+). Manual - part 105
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Wheels and Tires/Central Tire Inflation System (CTIS) 6-35
®
05745159
CTIS Leak Detection Test
1.
Start engine and inflate front and rear tires to 40 psi (276
kPa).
2.
Turn the tire selector switch to OFF.
3.
Turn engine OFF.
4.
Remove air vent line located at the air intake horn and
listen for air escaping through the vent line.
5.
Remove the transmission dipstick from the dipstick tube
and listen for air or transmission fluid escaping through
the dipstick tube.
6.
If air or fluid is detected in steps 4 or 5, inspect the
steering arm cover seals using the CTIS leak isolation test.
CTIS Leak Isolation Test
1.
Start the engine and inflate front and rear tires to 40 psi
(276 kPa).
2.
Turn the tire selector switch to OFF.
3.
Turn engine OFF.
4.
Close (release) all four wheel quick-disconnect valves.
5.
Remove the vent line from one geared hub.
6.
Open (engage) the quick-disconnect valve at this wheel to
allow air pressure from the tire to enter bored passage
inside the geared hub.
7.
Listen for escaping air around the steering arm seal
through the geared hub vent opening.
8.
If air is escaping through the vent line fitting, replace the
steering arm seal (Section 16).
9.
Inspect the other three geared hubs using steps 5, 6, 7, and
8 above.
10. Replace defective seals as required, then retest system.
CTIS Leakdown Testing
NOTE: Suspected air loss in the CTIS after the vehicle has
been parked for several days may be attributed to one of the
following: improperly seated O-rings, loose air line connec-
tion(s), quick-disconnect valve(s) not connected, tire leak(s),
faulty valve(s), or a faulty steering arm cover seal. Suspected
air leak(s) may be detected using a soap/water solution or
equivalent. O-rings that appear to be cut, distorted, or sus-
pected of leaking should be replaced. When traversing off road
in extremely muddy terrain, the dust excluder should be in-
spected for trapped mud.
1.
Verify quick-disconnect valves are connected to wheels.
2.
Apply parking brake. Start engine and allow to idle.
3.
Place tire selector switch to BOTH position and inflate/
deflate switch to INFLATE position.
4.
Observe air pressure gauges until air pressure reaches 40
psi (276 kPa).
5.
Place inflate/deflate switch to OFF position. Stop engine.
6.
Record tire pressure on instrument panel gauges and right-
rear tire pressure. Compare recorded pressures to readings
taken 30 minutes later, If more than one (1) pound has
leaked, check system as described above to detect where
the leak is located.
Inspect the quick-disconnect valve,
quick-disconnect valve nut, tube, nut
and sleeve assembly, insert, and el-
bow for damage (Figure 6-76).
Quick-disconnect compo-
nent is frayed, stripped,
cracked, or broken.
Replace the
component.
Tighten all connections. If air is still leak-
ing, remove the CTI part, clean, apply new
sealant to the threads, and install the CTI
part.
Inspect the tire for punctures and rim
leaks. Use a soap and water solution to
check for air leaks around the rim of the
tire. Repair or replace the tire as neces-
sary.
Troubleshooting Chart 5– Tire and Quick-Disconnect Valve