SECTION 12: BRAKE AND AIR SYSTEM
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
7
7. AIR
DRYER
Meritor Wabco air dryer port identification
PORT
DESRIPTION
1 From
compressor
21
To wet tank
3 Exhaust
4 To
governor
unloader
6 Electrical
control
Torque for connections:
3/8”-18 NPTF= 12 lbf-ft
1/4”-18 NPTF= 12 lbf-ft
1/2”-14 NPTF= 37 lbf-ft
Safety valve dynamic pressure: 290 psi
FIGURE 6: AIR DRYER
12226
The electric air dryer works according to the
same principles as its air-controlled predeces-
sor. The difference is that this air dryer is
controlled by the multiplex system. If the air
dryer should for some reason become
powerless, it will cease to function and the
desiccant will become
wet through
, while the
compressor will continue to charge. Relief is
provided via the safety valve.
By using the information from the vehicle
electronic system, the air dryer and compressor
control is optimized, so that drying of the air is
guaranteed and fuel consumption is reduced.
This will be noticed as a different compressor
start/stop pattern.
FIGURE 7: AIR DRYER LOCATION
The air dryer has a built-in function to prevent
freezing or blockage. The function provides
temporary relief (air dryer blow clean) at engine
shut down. This function eliminates the problem
of freezing on a stationary vehicle.
An additional feature at vehicle start-up prevents
the compressor from charging air during engine
cranking and start-up.
The air filter/dryer is located in the coolant
heater compartment; driver’s side, front of the
rear wheelhousing.
Its purpose is to remove moisture that could
damage the air system before the air enters the
system reservoir. The air filter/dryer also filters
the air to remove dirt, compressor oil, and other
contaminants that can damage the system.
MAINTENANCE
AIR DRYER DESICCANT CARTRIDGE
Change cartridge every 100,000 miles or once
every two years, whichever comes first.
The air dryer and wet tank may be purged
simultaneously for maintenance purposes using
the drain cock on the emergency air system fill
valve located in the engine compartment and
accessible through the engine compartment
R.H. side door (Figure 3).
For more information on Meritor Wabco Air
dryer, refer to the following manuals included on
your technical publications CD:
Meritor Wabco System Saver Series
Single Cartridge Air Dryers Maintenance
Manual 34
