SECTION 12: BRAKE AND AIR SYSTEM
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
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FIGURE 2: WET TANK AUTOMATIC DRAIN VALVE
3.2 MAINTENANCE
Except when equipped with an automatic drain
valve, air tanks must be purged at every 12,000
miles or once every year, whichever comes first.
3.2.1 Ping
Tank
The ping tank is located in the engine compart-
ment; it is accessible through the engine
compartment R.H. side door. It is used to
dissipate heat and to reduce noise produced by
the air compressor cycling on and off. The ping
tank is not provided with a drain valve. Confirm
proper operation once a year.
3.2.2 Wet (Main) Air Tank
This reservoir, located above the L.H. wheel of
drive axle in the rear wheelhousing, is provided
with an automatic drain valve and doesn’t need
to be purged manually.
3.2.3 Primary Air Tank
This reservoir is located above the R.H. wheel of
the drive axle and is provided with a bottom
drain valve (Figure 1 & Figure 3). It is recom-
mended to purge the primary air tank every
12,000 miles or once a year, whichever comes
first.
3.2.4 Accessory Air Tank
The accessory air tank is installed close to the
front axle and is provided with a bottom drain
valve (Figure 1).
Purge the reservoir by its drain valve every
12,000 miles.
FIGURE 3: EMERGENCY AIR SYSTEM FILL VALVES
AND DRAIN COCK
12211_1
3.2.5 Secondary Air Tank
This tank is located in the front wheelhousing,
behind the steering axle (Figure 1). It is provided
with a bottom drain valve.
Purge this reservoir every 12,000 miles.
3.2.6 Kneeling
Air
Tank
The kneeling air tank is located in the front
wheelhousing (Figure 1), and is provided with a
bottom drain valve.
3.2.7 Parking Brakes Overrule Air Tank
The parking brakes overrule air tank is installed
at the ceiling of the rear baggage compartment,
on the L.H. side, and is provided with a bottom
drain valve.
4.
AIR SYSTEM EMERGENCY FILL
VALVES
All vehicles come equipped with two emergency
fill valves that enable system pressurization by
an external source such as an air compressor.
The rear valve is located in the engine
compartment and is accessible from engine R.H.
side door (Figure 3). It is positioned close to the
door opening.
CAUTION
Maximum allowable air pressure is 140 psi
(965 kPa). Air filled through these two points
will pass through the standard air filtering
system provided by Prevost. Do not fill system
by any point on the system.
The front valve is located in the front service
compartment close to R.H. side of door frame
(Figure 4).
