20
Air System
Condition
Possible Cause
Solution
Discharge line blockage
Check for freeze up in the discharge line.
Check low spots and eliminate any traps in the
discharge line.
Inspect and repair compressor discharge port and
clear any line restrictions. Replace damaged lines
as necessary.
Check for carbon build-up. If carbon has built up,
make sure cooling lines are not kinked or
restricted. If carbon has built up in the discharge
line, replace the line.
Inlet line kinked or
restricted
Inspect the compressor air induction line for
kinks and restrictions. Repair or replace as
necessary.
Governor malfunction or
misadjustment
Check for proper loader/unloader cycles of
compressor.
Refer to vehicle manufacturerís manual for
governor maintenance and troubleshooting
procedures.
External contamination
Replace broken, defective or dirty air filters.
Clean contaminants from surface of compressor.
Air dryer purge valve
stuck open or leaking
Check for air dryer malfunction. Refer to air
dryer manufacturerís service instructions.
Chafed or worn discharge
line
Replace faulty sections of discharge line.
Loose or leaking air line
connections
Verify all connections are secure.
Tighten to vehicle specifications where
necessary.
Inspect port threads for damage. If damage is
extensive, replace cylinder head.
Damage to compressor
valves and/or valve seats
Replace the compressor.
No air delivery
Low air delivery
Low air pressure
Leaking or malfunctioning
internal pressure relief
valve
Replace the compressor.
Loose drive hub Loose
accessory drive coupling
Check fit of drive coupling.
Ensure hub is completely seated and crankshaft
nut is tight.
Inspect crankshaft for damage ó re place
compressor if crankshaft is damaged.
Noisy air
compressor
None of the above, but
condition persists
Replace the compressor.
Oil starvation to crank pin
or front main bearing
Check oil pressure. Verify oil passage is free of
obstructions. Make necessary repairs.
Failed power steering
pump (through-drive
version only)
Verify power steering pump is in proper
operating order. Refer to the component
manufacturerís service instructions.
Broken connecting
rod or crankshaft
All of the above
Replace compressor.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...