2
Removal and Installation
3
Meritor WABCO
Maintenance Manual MM-1012 (Issued 02-10)
2 Removal and Installation
Hazard Alert Messages
Read and observe all Warning and Caution hazard alert messages in
this publication. They provide information that can help prevent
serious personal injury, damage to components, or both.
WARNING
To prevent serious eye injury, always wear safe eye protection
when you perform vehicle maintenance or service.
Park the vehicle on a level surface. Block the wheels to
prevent the vehicle from moving. Support the vehicle with
safety stands. Do not work under a vehicle supported only by
jacks. Jacks can slip and fall over. Serious personal injury can
result.
Remove all pressure from the air system before you
disconnect any component. Pressurized air can cause serious
personal injury.
Replacement Requirements
Any time a new ACU is installed, replace the oil desiccant cartridge
to ensure a clean air supply to the new part. When you drain the air
tanks before servicing the ACU, check for water or oil that may have
accumulated in the tanks. Water or oil in the air tanks could indicate
a problem with the air dryer or compressor contributing to the ACU
problem.
The air control unit can be found in the following locations
depending on the vehicle. Figure 2.1, Figure 2.2, Figure 2.3 and
Figure 2.4.
Figure 2.1
Figure 2.2
Figure 2.3
Figure 2.4
Figure 2.1
4007
996a
WESTERN STAR, ALL MODELS
The ACU is
located under
the lower flange
of the left side
frame rail
behind the cab.
Figure 2.2
Figure 2.3
Figure 2.4
4007
99
7
a
24U MODELS, DUAL EXHAUST
The ACU is
located between
the flanges of the
left side frame
rail behind the
cab.
4007
99
8
a
The ACU is
located at the
top of the
frame
crossmember
to the right
of the cab
rear air
suspension.
3-PC. DAY CAB, 5-PC. SLEEPER CAB
4007
999a
The ACU is located
near the right side frame
rail between the vertical
muffler and muffler
support.
3-PC. 2V2 UPRIGHT EXHAUST
