Preparation For Disassembly; Cylinder Head - BENDIX BA-921 Service Data

BACK / RETOUR
3. If the vehicle is equipped with air brakes, make
certain to drain the air pressure from all reservoirs
before beginning any work on the vehicle.
4. Following the vehicle manufacturer's recom-
mended procedures, deactivate the electrical
system in a manner that removes all electrical
power from the vehicle.
5. When working in the engine compartment the en-
gine should be shut off. Where circumstances
require that the engine be in operation, extreme
caution should be used to prevent personal injury
resulting from contact with moving, rotating, leak-
ing, heated, or electrically charged components.
6. Never connect or disconnect a hose or line con-
taining pressure; it may whip. Never remove a
component or plug unless you are certain all sys-
tem pressure has been depleted.
7. Never exceed recommended pressures and always
wear safety glasses.
8. Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended proce-
dures. Use only the proper tools and observe all
precautions pertaining to use of those tools.
9. Use only genuine Bendix replacement parts, com-
ponents, and kits. Replacement hardware, tubing,
hose, fittings, etc. should be of equivalent size, type,
and strength as original equipment and be designed
specifically for such applications and systems.
10. Components with stripped threads or damaged
parts should be replaced rather than repaired. Re-
pairs requiring machining or welding should not
be attempted unless specifically approved and
stated by the vehicle or component manufacturer.
11. Prior to returning the vehicle to service, make cer-
tain all components and systems are restored to
their proper operating condition.
REMOVAL
In many instances it may not be necessary to remove the
compressor from the vehicle when installing the various
maintenance kits and service parts. The maintenance tech-
nician must assess the installation and determine the correct
course of action.
These instructions are general and are intended to be a guide. In
some cases additional preparations and precautions are neces-
sary. In all cases follow the instructions contained in the vehicle
maintenance manual in lieu of the instructions, precautions and
procedures presented in this manual.
1. Block the wheels of the vehicle and drain the air pres-
sure from all the reservoirs in the system.
6
2. Drain the engine cooling system and the cylinder head
of the compressor. Identify and disconnect all air, water
and oil lines leading to the compressor.
3. Remove as much road dirt and grease from the exte-
rior of the compressor as possible.
4. Remove the discharge and inlet fittings, if applicable, and
note their position on the compressor to aid in reassembly.
Note: If a cylinder head maintenance kit is being
installed, stop here and proceed to
PREPARATION FOR DISASSEMBLY. If
replacing the compressor continue.
3. Remove any supporting bracketing attached to the
compressor and note their positions on the compressor
to aid in reassembly.
5. Remove the flange mounting bolts and remove the com-
pressor from the vehicle.
6. Inspect gear and associated drive parts for visible wear
or damage. Since these parts are precision fitted, they
must be replaced if they are worn or damaged. If re-
placing the compressor or replacing the drive gear,
remove the drive gear from the compressor crankshaft
using a gear puller.
7. If the compressor is being replaced stop here and pro-
ceed to "Installing The Compressor" at the end of the
assembly procedure.

PREPARATION FOR DISASSEMBLY

Remove the balance of road dirt and grease from the exte-
rior of the compressor with a cleaning solvent. Mark the
rear end cover or end cover adapter in relation to the crank-
case. It is recommended but not specifically necessary to
mark the relationship of the cylinder head to the valve plate
assembly and crankcase and cylinder block assembly.
A convenient method to indicate the above relationships is
to use a metal scribe to mark the parts with numbers or
lines. Do not use marking methods such as chalk that can
be wiped off or obliterated during rebuilding.
Prior to disassembly make certain that the appropriate kits
and or replacement parts are available. Refer to figure 9
during the entire disassembly and assembly procedure.

CYLINDER HEAD

1. Remove the discharge safety valve (10) from the cylin-
der head.
2. To restrain the spring force exerted by balance piston
spring (5), hold the unloader cover (2) in place while
removing the two unloader cover cap screws (1). Care-
fully release the hold on the unloader cover until the
spring force is relaxed, then remove the unloader cover
(2).
3. Remove the unloader cover gasket (3).