General Inspection Instructions -680640110

TM 5-2420-224-20-1

WARNING

Drycleaning solvent P-D-680 is toxic and flammable. Wear protective

g o g g l e s and gloves and use only in well-ventilated area. Avoid contact with

s k i n , eyes, and clothes and do not breathe vapors. Do not use near open

f l a m e or excessive heat. Flash point is 100-138F (38-50 C). If you

become dizzy while using drycleaning solvent, get fresh air immediately and

g e t medical aid. If contact with eyes is made, wash your eyes with water

a n d get medical aid immediately.

CAUTION

To prevent damage to equipment, never use gasoline or other petroleum-base

p r o d u c t s to clean or preserve hydraulic system parts.

Hydraulic System. When cleaning hydraulic system parts, use drycleaning solvent SD-2

(P-D-680). Clean and dry parts thoroughly to make sure no residue remains. If a coating of

preservative is required before assembly, apply a light film of solid lubricant preservative. If

petroleum-free solvents are not available, use the same hydraulic fluid as used in the hydraulic

system.

Sealing Surfaces. Inspect all surfaces in contact with gaskets, packings, or seals. Make sure

there are no nicks, burrs, or scratches. If any defect is found, remove or repair it as outlined

under General Repair Instructions in this manual.

Bearings. Check bearings for rusted or pitted balls, races, or separators. Check balls and races

for brinnelling, abrasion, and serious discoloration. Refer to TM 9-214 for additional instructions

for bearings. Following are causes for bearing rejection:

Cuts or grooves parallel to ball or roller rotation.

Fatigue pits (not minor machine marks or scratches).

Cracks.

Inspection. Inspection consists of checking for defects such as distortion, wear, cracks, and

pitting. Parts under heavy load or pressure must be inspected more thoroughly. Clean all parts

before inspection.

Drain Plugs. When removing drain plugs from transmission, engine, or hydraulic system

components, inspect sediment adhering to plug. A buildup of grit and/or fine metal particles

may indicate part failure. A few fine particles are normal. This inspection is effective in

determining defective parts prior to internal inspection of parts.

Gears. Gear inspection cannot be described in detail here: there are too many differences in

size and shape of gears. The following steps can be used to make a general visual inspection

of all gears. Follow all steps listed in General Repair instructions for final inspection.

Normal Wear. Loss of metal from the surface of gear teeth. Wear must not prevent gears

from meshing or performing properly.

Initial Pitting. This may occur when a pair of gears is first started in service. It may

continue until most high spots have been reduced, as long as contact surfaces are not

affected. This pitting is not necessarily serious.

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