(2) Do not clean preformed packings or other rubber parts in drycleaning solvent. Wipe with a clean, dry,
lint-free cloth (Item 11, Appendix E).
(3) For exterior cleaning of frame and structural components, use soap solution (Item 21, Appendix E). Leave
application on items surface for approximately ten minutes before rinsing. Rinse with hot or cold water under pressure.
If available, use hot water under 80 to 120 lb (36-54 kg) pressure. An ordinary garden hose may be used if no other
equipment is available. If pressurized water supply is not available, wash painted surfaces with a soap solution (Item 21,
Appendix E) and water.
(4) Electrical parts such as coils, connectors, switches and insulated wiring, should not be soaked or sprayed
with cleaning solutions. Clean these parts with a clean, dry cloth (Item 11, Appendix E) moistened with drycleaning
solvent P-D-680 (Item 22, Appendix E).
A degreasing machine may be used to remove heavy grease and oil from metal parts.
Removal and Disassembly of Components.
(1) Welding and brazing processes may be used to repair cracks in external parts, such as brackets, panels and
framework. Because of time required and the chance of subsequent failure, such repairs should be attempted only
when replacement parts are not available. Welding and brazing of castings and running parts or parts under great
stress will only be done in emergencies. Refer to TC 9-237 for proper welding and brazing procedures.
(2) Replace any screw, nut, or fitting with damaged threads. Inspect tapped holes for thread damage. If
cross-threading is evident, retap the hole for the next oversize screw or stud. If retapping will weaken the part, or if the
cost of the part makes retapping impractical, replace the part. Chasing the threads with proper size tap or die may be
(3) Reshape elongated mounting holes to round and drill to receive bushing with required inner diameter.
Stake bushing in place with center punch.
Remove protective grease coatings from new parts before installation.
(5) To replace a preformed packing, first clean groove, then stretch packing and place into position. Place
component on flat surface and uniformly press packing into position.
(6) Coat oil seals evenly with oil or grease before installing. Install oil seals with seal lip facing in, applying an
even force to outer edge of seal. If oil seals are to be installed over keyed or splined shafts, use a guide to prevent sharp
edge of the keyway or splines from cutting the seal. Construct guides of very thin gauge sheet metal and shape to the
required diameter. Make certain guide edges are not sharp and are bent slightly inward so they do not cut the seal.
(7) Remove parts only if repair or replacement is required. Do not disassemble a component any further than
necessary to accomplish needed repairs.