Bendix Commercial Vehicle Systems BA-921 SMC COMPRESSOR - Manual (Page 4)

4
COOLING
The Bendix ® BA-921 ® SMC compressor is cooled by air
fl owing through the engine compartment as it passes the
compressor's cast-in cooling fi ns and by the fl ow of engine
coolant through the cylinder head. Coolant supplied by
the engine cooling system passes through connecting
lines into the cylinder head and passes through internal
passages in the cylinder head, cooling plate and valve plate
assembly and returns to the engine. Figure 7 illustrates
the approved coolant fl ow connections. Proper cooling is
important in minimizing discharge air temperatures - see
the tabulated technical data on page 13 of this manual for
specifi c requirements.
AIR INDUCTION
The Bendix ® BA-921 ® SMC compressors is only permitted
to be naturally aspirated – use of engine turbocharger as
an air source is not allowed. See Figure 8 for an example
of a naturally aspirated air induction system.
PREVENTATIVE MAINTENANCE
Regularly scheduled maintenance is the single most
important factor in maintaining the air brake charging
system. Refer to Table A in the Troubleshooting section
starting on page A-1, for a guide to various considerations
that must be given to maintenance of the compressor and
other related charging system components.
Important Note: Review the Bendix ® Warranty Policy before
performing any intrusive maintenance procedures. An
extended warranty may be voided if intrusive maintenance
is performed during this period.
EVERY 6 MONTHS, 1800 OPERATING HOURS
OR AFTER EACH 50,000 MILES, WHICHEVER
OCCURS FIRST, PERFORM THE FOLLOWING
INSPECTIONS AND TESTS.
Compressor
Governor
Reservoir
Port
Governor
Unloader Port
Air Dryer
FIGURE 8 - COMPRESSOR CHARGING SYSTEM
FIGURE 7 - BENDIX ® BA-921 ® SMC COMPRESSOR CYLINDER HEAD
CYLINDER HEAD PORT IDENTIFICATION
The cylinder head connection ports are identifi ed with
cast-in numerals as follows:
AIR IN 0
Compressed AIR OUT 2
Coolant IN or OUT 9
Governor Control 4
Discharge
Safety Valve
Discharge
Port
Inlet
Port
Unloader
Cover
Coolant
In or Out
Head
Bolt (6)
Governor
Connection
Coolant
In or Out