4-9. GENERAL MAINTENANCE PROCEDURES- Continued
h. Lowering the Truck.
(1) Place 10 ton hydraulic jack beneath differential. Raise the jack until all weight is off maintenance
(2) Remove maintenance trestles from beneath axle (one on each side of differential).
(3) Carefully and slowly, lower jack until all weight is removed from jack. Immediately after truck is
grounded, chock the wheels.
(4) Repeat steps 1 through 3 to lower other axle as necessary.
(5) Ensure gear selector is positioned to N (neutral) and parking brakes are applied, then remove all
i. Identification. Identify all parts of similar shape with tags. This will make proper reassembly easier. Be
sure to identify ends of electric, hydraulic, and air lines as they are disconnected.
Some assemblies that are removed, even though defective, shall be treated as valuable
items. They may be rebuilt for future use.
k. Expendable Parts.
Whenever possible, all gaskets, packings, and seals shall be discarded during
removal or disassembly. Similarly, lock wire, lockwashers, cotter pins, and like items shall be discarded
during disassembly. All should be replaced during assembly. When removing seals, gaskets, or packings,
take care not to damage (e.g. scratch) the sealing surfaces. If surfaces are damaged they must be
repolished to give a good sealing surface.
I. Parts Protection. To prevent moisture and dirt from entering housings, lines, and other openings, apply
protective covers after disassembly. Wrap all parts in clean paper or dip parts in rust preventive oil.
4-9.2. General Cleaning Instructions
Do not use scrapers, wire brushes, abrasive wheels, or
compounds when cleaning parts unless called for in detailed
instructions. These procedures may alter size of machined
surface and may weaken a stressed part.
a. Dry Cleaning Solvent.
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 1 00 to 138 deg. F (38 to 59 deg. C).
Whenever dry cleaning solvent is recommended for cleaning, use item 3, Appendix E.