GMC 4000 Series Service Manual page 392

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GENERAL INFORMATION
Midland-Ross and Bendix-Westinghouse air
com pressors are interchangeable as complete a s­
sem blies on all models covered by his manual.
Since both Midland-Ross and Bendix-Westinghouse
com pressors are used in regular production on all
vehicles, the mechanic must determine which is
used on each specific vehicle before proceeding
with adjustment or repair of any com pressor. Re­
moval and installation procedures are applicable
to both Midland-Ross and Bendix-Westinghouse
com pressors without exception.
DESCRIPTION
The air com pressors covered in this manual
are two-cylinder, piston type com pressors. The
rated capacity of an air com pressor is its piston
displacement in cubic feet per minute when oper­
ating at 1250 rpm. The air com pressors used on
these models are rated at 7% cubicfeetper minute.
LEFT S ID E M O U N T
1 Drive Pulley
2 Drive Belt
3 Air Line to Tank
4 Mounting Bracket
G M C S E R V I C E M A N U A L
SECTION 6T
The com pressor Model Number is shown on a
name plate which is attached to the cylinder block.
the engine lubrication system and cooled by air
from the fan assembly.
assem bly, which is attached to the cylinder head
or cylinder block. This governor, in conjunction
with the air com pressor unloading mechanism,
controls the compression of air.
ations vary from one model to another but all have
the same basic principle of attachment and adjust­
ment. An adjusting arm (with a slot at one end)
connects the air com pressor to the vehicle engine
(generally at the engine front cover). This arm is
attached solidly to the engine with a bolt and nut.
5 Swivel Bolt
Governor
6
7 Inlet Oil Line
Return Oil Line
8
Figure 1— A ir C om pressor Installed ITypical)
All com pressors are lubricated by oil from
Each com pressor is equipped with a governor
COMPRESSOR M O UNTING
A N D DRIVE
(Refer to Figure 1)
Air com pressor mounting and drive install­
R IG H T S ID E M O U N T
9 Governor to Tank Air Line
10 Mounting Base Bolts
11 Mounting Base
12 Intake Air Strainer
Sec. 6T
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