4-9. GENERAL MAINTENANCE PROCEDURES - Continued
After each four or five passes, clean the lapping powder from the part by drawing it across a clean piece
of tissue placed on a flat surface and inspect the part. DO NOT LAP EXCESSIVELY.
When the part is flat, wash it in dry-cleaning solvent (item 3, Appendix E) and dry it with compressed air.
Place the dry part on the second block. After applying lapping powder, move the part lightly across the
block in a figure eight motion several times to give it a smooth finish. DO NOT LAP EXCESSIVELY.
Wash the part in dry-cleaning solvent (item 3, Appendix E) again, and dry it with compressed air.
Place the dry part on the third block. Do not use lapping powder on this block. Keep the part flat and
move it across the block several times, using the figure eight motion. Lapping the dry part in this manner
gives it the "mirror, finish required for perfect sealing.
Wash the lapped part in dry-cleaning solvent (item 3, Appendix E) and dry with compressed air.
4-9.4. General Repair/Assembly Instructions
a. Truck Body. Chassis and exterior painted parts may be resurfaced where paint is damaged or parts have
been repaired. Before resurfacing, scrape off loose and blistered paint. Clean area to be painted by sanding
or buffing. Remove dust. During repair operations, protect bare steel surfaces from rusting with protective
oil. Minor body dents may be removed by bumping with a soft-faced hammer while using a wooden block
b. Welding. Welding and brazing may be used to repair cracks in steel parts (e.g., brackets, panels and light
framework). Aluminum body panels may also be welded. They should only be welded when replacement
parts are not available. Do not weld or braze castings, moving parts, or parts under great stress, except in
emergencies. Refer to TM 9-237 for welding practices.
equipment. When welding anywhere on the vehicle, all modules
for the electronically controlled devices must be disconnected.
c. Hoses. Replace all broken, frayed, crimped or soft flexible hoses. Replace stripped or damaged fittings.
When replacing hose clamps ensure hoses are not crimped.