Bendix Commercial Vehicle Systems BENDIX 720CC COMPRESSOR - Manual (Page 11)

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Repeat this process on the engine mounting face as
well. Follow the instructions contained in the vehicle
maintenance manual in lieu of the instructions and
procedures presented in this manual.
2. Carefully remove all gasket material adhering to the
deck (top) of the crankcase. Remove any carbon
deposits from the deck of the crankcase. Make certain
not to scratch or mar the gasket surfaces.
CYLINDER HEAD, COOLING PLATE & VALVE
PLATE ASSEMBLY
1. Carefully remove all gasket material adhering to the
cylinder head, cooling plate and valve plate assembly.
Make certain not to scratch or mar the gasket surfaces.
Pay particular attention to the gasket surfaces of the
cylinder head and cooling plate.
2. Remove carbon deposits from the discharge and inlet
cavities of the cylinder head, cooling plate and valve
plate assembly. They must be open and clear in the
components. Make certain not to damage the parts.
3. Remove rust and scale from the cooling cavities and
passages in the cylinder head, cooling plate and valve
plate assembly and use shop air to clear debris from
the passages.
4. Check the threads in all cylinder head ports for galling
(e.g. abrasion, chafing). Minor thread chasing (damage)
is permitted.
INSPECTION OF PARTS
CYLINDER HEAD, COOLING PLATE AND VALVE
PLATE ASSEMBLY
1. Carefully inspect the head gasket surfaces on the
cylinder head for deep gouges and nicks. Also, inspect
the cylinder head for any cracks or port thread damage.
If detected, the compressor must be replaced. If large
amounts of carbon build-up are present in the discharge
cavity, such that it restricts the air flow through the
cylinder head, the compressor should be replaced.
2. Carefully inspect both sides of the gasket surfaces
on the cooling plate for deep gouges and nicks.
Also, inspect the cooling plate for any cracks or other
damage. If damage is found, the compressor must be
replaced.
3. Carefully inspect the valve plate assembly gasket
surfaces (both sides) for deep gouges and nicks. Pay
particular attention to the gasket surface. An inlet
reed valve gasket (7) is used between the valve plate
assembly and crankcase. These gasket surfaces
must be smooth and free of all but the most minor
scratches. If excessive marring or gouging is detected,
the compressor must be replaced. If large amounts of
carbon build-up are present on the two main surfaces, in
the two discharge valve holes or between the discharge
valve and the discharge seat, the compressor should
be replaced.
REAR END COVER
Check for cracks and external damage. Check the
crankshaft rear bearing diameter in the rear end cover for
excessive wear, flat spots or galling. Check the hydraulic
pump attachment pilot and threaded holes for damage.
Minor thread chasing is permitted, but do not re-cut the
threads. If any of these conditions are found, replace the
compressor.
CRANKCASE
Check the cylinder head gasket surface on the deck (top)
of the crankcase for nicks, gouges, and marring. A metal
gasket is used to seal the cylinder head to the crankcase.
This surface must be smooth and free of all but the most
minor scratching. If excessive marring or gouging is
detected, the compressor must be replaced.
Check the condition of the two countersunk holes on the
deck of the crankcase that retain the o-rings (8) and prevent
coolant leakage between the valve plate assembly and the
crankcase. The surface in contact with the o-ring should be
smooth and free of any scratches and gouges that could
cause leakage around the o-rings.
ASSEMBLY
General Note: All torques specified in this manual are
assembly torques and typically can be expected to fall off
after assembly is accomplished. Do not re-torque after
initial assembly torques fall unless instructed otherwise.
A compiled listing of torque specifications is presented on
page 13.
INCH POUNDS TO FOOT POUNDS
To convert inch pounds (in-lbs) to foot pounds (ft-lbs) of
torque, divide inch-pounds by 12.
Example: 12 in-lbs = 1 ft-lbs
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FOOT POUNDS TO INCH POUNDS
To convert foot pounds to inch pounds of torque, multiply
foot pounds by 12.
Example: 1 ft-lbs x 12 = 12 in-lbs