6
AIR LEAKAGE TESTS
Leakage past the discharge valves can be detected by
removing the discharge line, applying shop air back through
the discharge port and listening for escaping air. Also, the
discharge valves and the unloader pistons can be checked
for leakage by building up the air system until the governor
cuts out, then stopping the engine. With the engine stopped,
carefully listen for escaping air at the intake. To pin-point
leakage if noted, squirt oil around the unloader pistons. If
there is no noticeable leakage at the unloader pistons, the
discharge valves may be leaking.
If the compressor does not function as described above, or
leakage is excessive, it is recommended that it be returned
to the nearest Bendix authorized distributor for a factory
rebuilt compressor under the repair exchange plan. If this is
not possible, the compressor can be repaired with genuine
Bendix parts in which case the following information should
prove helpful.
REMOVING AND INSTALLING
REMOVING
These instructions are general and in some cases additional
precautions must be taken.
Drain air brake system.
Drain engine cooling system, compressor cylinder head and
block.
Disconnect all air lines, water and oil lines to and from
compressor.
Remove compressor mounting bolts and compressor from
engine.
Use a gear-puller to remove the gear or pulley from
compressor crankshaft.
INSTALLATION
Clean oil supply line. Before connecting this line to the
compressor run the engine briefly to be sure oil is flowing
freely through the supply line.
Clean the oil return line or return passages through the
brackets; these passages must be unrestricted so oil can
return to the engine.
Prelubricate compressor cylinder walls, piston rings, and
bearings with clean engine oil before assembling compressor.
Always use a new mounting gasket and be sure oil hole in
gasket and compressor is properly aligned with oil supply
line.
Inspect pulley or gear and associated parts for wear or
damage. They must be a neat fit on compressor crankshaft.
Replace pulley or gear if worn or damaged.
Install pulley or gear on compressor crankshaft making sure
it properly contacts the shaft and does not ride the key.
Tighten crankshaft nut to 65-70 ft. lbs. and install cotter pin.
Be sure the air cleaner is clean and properly installed. If the
compressor intake is connected to either the engine air
cleaner or supercharger, these connections must be tight
with no leakage.
Clean or replace any damaged or dirty air or water lines
which may be corroded, before connecting them to the
compressor. Use a new discharge fitting gasket.
Align compressor drive and adjust proper belt tension.
Tighten mounting bolts securely and evenly.
After installation run compressor and check for air, oil, or
water leaks at compressor connections. Also, check for
noisy operation.
DISASSEMBLY
GENERAL
Clean compressor exterior of road dirt and grease using a
good cleaning solvent. Before compressor is completely
disassembled the following items should be marked to show
their relationship when the compressor is assembled:
The cylinder block in relation to crankcase, end covers’
relation to crankcase, position of crankshaft in relation to
crankcase, the cylinder head’s relation to the block.
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 a marking method that can be wiped off
or obliterated during rebuilding, such as chalk. Remove all
compressor attachments such as governors, air strainers
or inlet fittings, discharge fittings and pipe plugs.
CYLINDER HEAD
Remove the cylinder head cap screws and tap the head
with a soft mallet to break the gasket seal. Remove the inlet
valve springs from the head and inlet valves from their guides
in the block. Remove inlet valve guides from around the
inlet valve seats on the block taking care not to damage
seats. Scrape off any gasket material from the cylinder
head and block. Unscrew the discharge cap nuts from the
head and remove the discharge valves and springs. Inspect
the discharge valve seats for nicks, cracks, and excessive
wear and remove and replace if necessary.
FIGURE 11 - INLET ADAPTER
