PREVOST X3-45 Multiplex - Pressure Setting Procedure; Engine

Section 12: BRAKE AND AIR SYSTEM
PA1562
10
a cleaning solvent (Fig. 7). Examine the
diaphragm; if cracked, worn or damaged,
replace with a new one. If the valve is
excessively grooved or pitted, it should be
replaced. Replace any other part that appears
worn or damaged. After reassembly, adjust to
the specified pressure setting and check for air
leakage.
FIGURE 7: AIR PRESSURE REGULATING VALVE 12141B
9.2 PRESSURE SETTING PROCEDURE
Remove the dust cap from the pressure check
valve (Fig. 8). Attach a pressure gauge at this
port and check the pressure reading. If the
pressure reading is incorrect, adjust as follows:
FIGURE 8: AIR PRESSURE REGULATOR 12200
1. Loosen the locking nut, turn the adjustment
screw counterclockwise to decrease
pressure by approximately 10 psi (70 kPa)
below the required pressure.
2. Turn the adjustment screw clockwise to
increase the pressure slowly until the re-
quired pressure setting is reached. Tighten
the locking nut.
3. Remove pressure gauge and replace dust
cap on the air pressure check valve.
10. AIR COMPRESSOR
10.1 WITH DETROIT DIESEL SERIES 60
ENGINE
The BA-921 Bendix air compressor is located on
starter side of the engine, on the rear of the
engine gear case (Fig. 9). Its function is to
provide and maintain air under pressure to
operate devices in brake and air systems.
This air compressor also drives the engine fuel
pump which is bolted to the rear end of the
compressor. The compressor crankshaft is
designed to accept a drive coupling which is
placed between the compressor and fuel pump.
The compressor is driven by the bull gear, and
is water cooled. Engine coolant is fed to the
compressor through a flexible hose tapped into
the block water jacket and connected to the rear
of the compressor. Coolant returns from the top
of the compressor (governor side) through a
flexible hose to the engine pump.
The air is taken from the air intake manifold and
entered in the top of the compressor. The
compressed air is pushed into the discharge line
located on side of the compressor, which sends
air to the air dryer. Lubricating oil is supplied to
the compressor by a line from the cylinder block
oil gallery connected to the air compressor.
Lubricating oil returns to the engine crankcase
through the air compressor drive assembly.
FIGURE 9: AIR COMPRESSOR LOCATION 03061
Maintenance and repair information on the
Bendix BA-921 air compressor is supplied in the
applicable booklet annexed to this section under
reference number SD-01-676.