The following procedure is used with polished and machined steel parts not protected
by cadmium, tin, copper, or other plating or surface treatment. Bare metal surfaces
must be free of moisture when protective coating is applied.
Protective Parts. During repair operations, protect bare steel surfaces from rusting when not actually
undergoing repair work. Dip parts in, or spray them with, corrosion preventive compound. The same protective
coating may be applied to other metals to prevent rust. Aluminum parts may require protection in atmospheres
having a high salt content. Steel parts must always be protected.
Before welding, the following components must be disconnected: DDEC ECU, ABS
ECU, CTIS ECU, DATALOGGER, and batteries (TM 9-2320-363-20-2). If welding on a
trailer, it must be uncoupled from tractor/dump truck. Failure to follow this caution may
damage electronic components.
Welding. Welding and brazing may be used to repair cracks in external steel parts, such as brackets, panels,
and light framework. These repairs should be made only when replacement parts are not available. Do not
weld or braze castings, running parts, or parts under great stress, except in emergencies. When welding is
required, refer to TM 9-237.
Stud Installation. When installing studs in engine block and axle housings, use a driver designed for the stud to
be installed. A worn stud driver may damage the end thread. This makes it necessary to use a chasing die
before a nut can be screwed on. This procedure will remove cadmium plating and allow corrosion, which will
make future disassembly difficult and cause stud to be backed out with nut. Before driving a stud, inspect hole
for chips and liquid. Blow out any foreign matter. Start stud by hand. If it will not start into hole, it is too large or
has defective end thread. Before final insertion, coat thread with antiseize compound; turn stud in slowly to
prevent overheating and galling of casting metal.
Electrical Parts. Replace all broken, worn, or burned electrical wiring. Wires with several broken strands must
be replaced. Broken strands will increase the resistance of the wire and impair efficiency of electrical
components, especially the ignition system.
Hoses. Replace all broken, frayed, crimped, or soft flexible lines and hoses. Replace stripped or damaged
fittings. Replace entire flexible hose if fittings are damaged. Make sure hose clamps do not crimp hoses.
Fasteners. Replace any bolt, screw, nut, or fitting with damaged threads. Inspect tapped holes for thread
damage. If cross-threading or galling is evident. retap the holes for the next oversize screw or stud. When
retapping will weaken the part, or when the cost of the part makes retapping impractical, replace the damaged
part. Chasing threads with the proper size tap or die may often be enough.
10. Dents. Straighten minor body dents by bumping with a soft-faced hammer while uslng a wooden block backing.
11. Sheet Metal Repair. Repair minor skin cracks by installing patches.
12. Mounting Holes. Reshape oval mounting holes to round. Drill to receive bushing with required inner diameter.
Stake bushing in place with center punch.
Preparation. Remove grease from new parts before installation.