Section 16: SUSPENSION
PA1593
25
6.2 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 located in engine
compartment and accessible from engine R.H.
side door (Fig. 28).
FIGURE 28: REAR VALVE LOCATION
12211
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
(Fig. 29).
FIGURE 29: FRONT SERVICE COMPARTMENT
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.
7. FRONT KNEELING SYSTEM
The kneeling system is used to lower the front of
vehicle. This allows passengers to board the
vehicle with greater ease. The kneeling action is
achieved by exhausting air from the front air
springs (bellows). This system bypasses the
height control valve to provide a fast up and
down movement of the front suspension. Only
four seconds are required to lower vehicle from
normal level to the lowered position, and
approximately the same time to raise the vehicle
back to normal level. The quick response is
achieved by an auxiliary air tank installed beside
the secondary air reservoir (for exact position,
refer to Section 12,
“Brake and Air System”).
This tank provides sufficient air supply to the
kneeling system for some successive
operations.
The system is provided with two safety features;
first, a speed switch will enable the kneeling
system to work only at less than 5 mph (8 km/h).
Secondly, the parking brake is automatically
applied, and a limit switch will keep it applied as
long as the vehicle has not returned to a certain
height where the driver will be able to manually
remove the parking brake.
7.1 PRINCIPLE OF OPERATION
Refer to the air system schematic diagram
annexed at the end of Section 12,
“Brake and
Air System”.
DOWN (FRONT KNEELING):
Both the bellows control and bellows exhaust
solenoid valves are energized, so the air control
valves release air from front air springs. The
height control valve is bypassed to ensure no air
is forwarded to air springs while lowering the
front suspension.
Summary of Contents for X3-45 2016
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Page 16: ...Section 00 GENERAL INFORMATION PA1593 12 FIGURE 12 METRIC US STANDARD CONVERSION TABLE 00005...
Page 17: ...Section 00 GENERAL INFORMATION 13 PA1593 FIGURE 13 CONVERSION CHART 00006...
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Page 72: ...Section 04 EXHAUST AND AFTERTREATMENT SYSTEM PA1593 14 7 TORQUE SPECIFICATIONS...
Page 73: ...SECTION 04 EXHAUST AND AFTERTREATMENT SYSTEM PA1593 15...
Page 74: ...Section 04 EXHAUST AND AFTERTREATMENT SYSTEM PA1593 16...
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Page 176: ...SECTION 06B ELECTRICAL 38 overcurrent working Circuit 306 shorted to ground...
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Page 205: ...Section 09 PROPELLER SHAFT PA1593 3 FIGURE 1 PROPELLER SHAFT ASSEMBLY 09002...
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Page 295: ...SECTION 16 SUSPENSION PA1593 9 2 5 TORQUE SPECIFICATIONS...
Page 296: ...Section 16 SUSPENSION PA1593 10...
Page 297: ...Section 16 SUSPENSION PA1593 11...
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Page 413: ...Section 22 HEATING AND AIR CONDITIONING PA1593 15 FIGURE 18 REFRIGERANT CIRCUIT CENTRAL SYSTEM...
Page 433: ...Section 22 HEATING AND AIR CONDITIONING PA1593 35 FIGURE 36 CENTRAL HEATING SYSTEM COMPONENTS...