Bendix Commercial Vehicle Systems BA-921 SMC COMPRESSOR - Manual (Page 7)

7
While it is possible to test for inlet, discharge, and unloader
piston leakage, it may not be practical to do so. Inlet and
discharge valve leakage can generally be detected by longer
compressor build-up and recovery times. Compare current
compressor build-up times with the last several recorded
times. Make certain to test for air system leakage, as
described under In Service Operating Tests, before making
a determination that performance has been lost.
Unloader leakage is generally exhibited by excessive
compressor cycling between the loaded and unloaded
condition.
1. With service and supply system leakage below the
maximum allowable limits and the vehicle parked, bring
system pressure to governor cut-out and allow the engine
to idle.
2. The compressor should remain unloaded for a minimum
of 5-10 minutes. If compressor cycling occurs more
frequently and service and supply system leakage is
within tolerance, replace the compressor or repair the
compressor unloader system using a genuine Bendix
®
maintenance kit available from authorized Bendix parts
outlets.
COMPRESSOR REMOVAL & DISASSEMBLY
GENERAL
The following disassembly and assembly procedure is
presented for reference purposes and pre-supposes that
a rebuild or repair of the compressor is being undertaken.
Several maintenance kits are available and the instructions
provided with these parts and kits should be followed in lieu
of the instructions presented here.
MAINTENANCE KITS & SERVICE PARTS FOR
B E N D I X ® B A - 9 2 1 ® S M C S I N G L E C Y L I N D E R
COMPRESSOR ONLY
Cylinder Head Gasket Kit ...................................K023764
Unloader Kit ........................................................K046477
Discharge Safety Valve ...................................... 800534
Compressor Seal Kit...........................................K051352
Compressor to Engine Mounting Face Sealant (Supplied by
the Engine Manufacturer)
All components shown in Figure 9 with a key number are
available in kits and/or as individual service parts.
GENERAL SAFETY GUIDELINGS
IMPORTANT! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID PERSONAL
INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times:
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses. Where specifi cally
directed, the parking brakes may have to be
released, and/or spring brakes caged, and this
will require that the vehicle be prevented from
moving by other means for the duration of these
tests/procedures.
2. Stop the engine and remove ignition key when
working under or around the vehicle. When
working in the engine compartment, the engine
should be shut off and the ignition key should
be removed. Where circumstances require
that the engine be in operation, EXTREME
CAUTION should be used to prevent personal
injury resulting from contact with moving,
rotating, leaking, heated or electrically charged
components.
3. Do not attempt to install, remove, disassemble
or assemble a component until you have read
and thoroughly understand the recommended
procedures. Use only the proper tools and
observe all precautions pertaining to use of those
tools.
4. If the work is being performed on the vehicle’s
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with
a Bendix
® AD-IS ® air dryer system or a dryer
reservoir module, be sure to drain the purge
reservoir.
5. F o l l o w i n g t h e v e h i c l e m a n u f a c t u r e r ’s
recommended procedures, deactivate the
electrical system in a manner that safely removes
all electrical power from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix ® brand replacement
parts, components and kits. Replacement
hardware, tubing, hose, fi ttings, etc. must be
of equivalent size, type and strength as original
equipment and be designed specifi cally for such
applications and systems.