4-22. AIR SYSTEM - Continued
4-22.2 Pressure Protection Valves and Manifold.
This task covers
Shop Equipment, Automotive
22, Appendix E Pipe Sealant
Maintenance and Repair,
Main Engine Shutdown (see para. 2-10)
APU Shutdown (see para. 2-12)
Batteries Disconnected (see para. 4-24)
Truck Wheels Blocked
All Air Tanks Drained
Emergency and Fast Air Reservoirs Removed
(see para. 4-22.1)
Death or serious injury could occur if compressed air is directed against the skin. Always
drain all air tanks via the draincocks prior to maintaining the pressure protection valves.
This is a generalized instruction for any (of the three) pressure protection valves installed on
the truck. The pressure protection valves are located on a cross member beneath the cab.
Tag and remove all air lines (A thru H) connected to the pressure protection valve manifold
Remove the capscrews and locknuts attaching the manifold to the cab cross member
Dismantle the manifold as required using the illustration as a guide
Assemble the pressure protection valves using the illustration as a guide. Be sure all pipe threads are
coated with pipe sealant (item 22, Appendix E) during assembly. Use the illustration to orientate both the
pressure protection valves.
Connect temporary pressure gages and drain valves to ports A, C, and H
Connect a blank to ports B, E, F, and G
Connect a temporary air line from shop supply together with a pressure gage to port D