4-22. AIR SYSTEM - Continued
4-22.13 Air Lines and Piping
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
Death or serious injury could occur if compressed air is directed against the skin. Always
drain all air tanks via the draincocks prior to replacing any air line or pipe.
Disconnect both ends of air line that has failed. Use the air schematics in Appendix H as a guide to
determine location of both ends.
For tubes with compression fittings, thread a new piece of brake tubing between the two connectors. Be
sure the tubing follows the same routing as the failed tube.
Cut tube from roll and fit new nut and sleeve on both ends of the tube. Coat threads of connector with
pipe sealant (item 22, Appendix E), and tighten nut onto connector.
All connectors should be tightened approximately two turns beyond hand tight.
Lay new tube in harness and if necessary strap in place with tie wraps. Be sure tube is supported at least
every 2 - 3 ft (0.6 - 0.9 m).
Be sure tube does not come any closer than 1 in. (25 mm) to any moving or hot part.
When tube is installed, reconnect truck batteries and start main engine. When air line is pressurized
brush both connectors with soap solution to check for leaks. Tighten/remake connections as required.
For hoses with flared connectors, lay out and cut new hose as above. Remove hose and fit new
connectors to each end as detailed in para. 4-9. Be sure same type of connectors are used.
Install hose assembly in truck and carry out instructions 4 thru 7 preceding.
Remove old air line or pipe from truck, or, if in a harness, cut back to the harness from both ends so that
failed line or pipe will not be used subsequently.