4-28 ENGINE - Continued
(10) Attach the oil pressure feed hose (6) to the air compressor crankshaft bearing cap fitting.
(11) Attach the coolant hoses (4 and 5) and clamp securely.
(12) Refill cooling system and bleed out all air.
(13) Reconnect the truck batteries.
If the air compressor has been overhauled inject about 5 cc of engine oil (item 17, Appendix E)
into air compressor intake while the engine is running. Stop the engine when fog appears at
(14) Install air inlet hose (2) and high pressure hose (3) to the air compressor.
(15) Install the air lines to the air compressor governor (1).
(16) Check the operation of the air compressor and governor. With no leaks and all tanks empty, all air
tanks should reach maximum pressure of 105 - 125 psi (724 - 862 kPa) in less than 5 minutes.
(17) During initial operation check for coolant leaks, oil leaks, noise, or overheating.
(18) After air pressure has reached maximum, shutdown engine and check for air leaks.
Minor air compressor repairs can be completed with the unit mounted to the truck engine. Major
overhaul or repairs require removal of air compressor from truck engine. Disassemble air
compressor using the following procedures. The repair procedures described below refers to an
air compressor that has been removed from the truck engine.
a. Initial Cleaning
Dry cleaning solvent P-D-680 (safety or Stoddard's solvent) is potentially dangerous. Avoid
repeated and prolonged breathing of vapors and skin contact with the liquid. Do not use near
open flame, arcing equipment or other ignition sources. Always wear eye protection and
protective clothing. The flash point of P-D-680 is 100 to 138 deg. F (30 to 59 deg. C).
(1) Prior to disassembly, clean the air compressor exterior using dry cleaning solvent (item 10, Appendix E).