Emergency Fill Valves; Troubleshooting - PREVOST H3-41 Maintenance Manual

12.2

EMERGENCY FILL VALVES

The vehicle is equipped with two air system
emergency fill valves to supplement the air
system when air pressure is low and engine
cannot be operated.
The rear valve is
compartment and accessible from engine R.H.
side door (Figure 44).
CAUTION
No other point should be used to supply air
system. The maximum allowable air pressure
is 125 psi (860 kPa).
The front valve is located in the front service
compartment close to accessory air filter (Figure
46).
These two air valves are fitted with the same
valve stems as standard tires, and can be filled
by any standard external air supply line.
The rear valve will supply air for all systems
(brakes, suspension and accessories) while the
front valve will supply air for accessories only.
CAUTION
Air filled through these two points will pass
through the standard air filtering system
provided by Prevost. Do not fill air through any
other points.
NOTE
Apply corrosion-protective compound on exposed threads.
13

TROUBLESHOOTING

Condition
Air springs deflate over
time
located in engine
Cause
1. Defective check valve assembly.
2. Defective exhaust valve assembly.
3. Leak in air line and/or air springs.
4. Defective valve cover, rubber O-rings
or gasket.
PA1621 Maintenance Manual All Series | Section revised October 2018
SECTION 16 : SUSPENSION
Correction
1. Replace check valve assembly.
2. Replace exhaust valve assembly.
3. Replace air line or air springs.
4. Replace valve cover, O-rings or
gasket.
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