Magnetic particle inspection. This inspection should be performed on steel parts when possible. Steel parts that
have been reworked or reground and parts containing areas of fatigue should be tested. Shear sections and
reground contact surfaces must show no defects. Any evidence of cracks is cause for rejection. Since some
stainless steel cannot be magnetized, do not perform this test on such components. This inspection must be
performed as specified in MIL-I-6870 and MIL-STD-6866 by qualified operators and inspected by qualified
inspectors. On completion of inspection, pass parts through a demagnetizing field. Wash and allow to air dry.
Parts must be rejected if there are indications of nonmetallic foreign solids longer than 1 inch (2.54 cm). Parts
shall also be rejected if the following patterns appear:
a. Bursts - scattered, short, sharp lines caused by high temperatures. Such discontinuities usually are internal and
are seldom detected by magnetic particle inspection until surface is cut to expose burst area.
b. Flakes - separate, short, wavy lines, usually in the same general direction, caused by improper cooling. Flakes
are usually internal and are seldom detected by magnetic particle inspection until surface has been cut to expose
the flake area.
c. Grinding cracks - fine, sharp lines, tightly packed. In some surfaces, cracks may be shallow and hard to see.
Grinding cracks are usually caused by a glazed wheel, resulting in overheating. These cracks are similar to heat-
treat and hardening cracks. Grinding cracks may also be caused by too little coolant, too much feed, or too much
UPPER SUSPENSION ARM BEARING
This task covers:
General mechanics tool kit, item 16, appx. B
Fire extinguisher, item 20, appx. B
The following tools can be found in field maintenance basic tool kit, item 14,
Torch set, cutting and welding
Hand truck, two-wheeled
Regulating valve, oxygen
Duplex rubber hose
Regulating valve, acetylene
Hydraulic floor jack, 10 ton
Hammer, sledge, 10 lb