Inspection - TM-9-2815-200-350296

(3) Inspect finish of all parts. Mark all parts

e. Ball and Needle Bearings.

that require refinishing.

(1) Bearings require special attention in

b. Overhaul Standards. To identify parts, the

cleaning and oiling. After removing the surface

Overhaul Standards Tables of this chapter refer

dirt, oil, or grease, the bearings, except the

to the exploded views in the repair parts section

sealed, permanently lubricated type, should be

placed in hot oil (about 150F.) to loosen

(Appendix B). Key letters are used on the ex-

ploded views to locate points of measurement for

congealed oil and grease. After cleaning, the

o v e r h a u l limits. E a c h t a b l e c o n t a i n s t h e

bearings should be coated with a film of

maximum, minimum, and key clearances of new

lubricant and wrapped tightly in oiled or waxed

or overhaul parts. The clearances, listed mainly

paper until inspection and assembly.

Note. Do not immerse sealed type ball

for reference, will automatically be achieved if

bearings in dry-cleaning solvent, mineral spirits

the mating parts are within the dimensional

paint thinner, or hot oil. Entrance of cleaning

tolerances listed in the tables. In some cases, a

agent will destroy lubricants sealed in bearing at

part that is out of dimensional tolerance may be

time of manufacture. Loss of lubricant will result

used, providing the mating part has been

in premature failure of bearing and possible

carefully selected and, when mated, is within the

maximum clearance limits specified in the wear

severe damage to the engine.

limits column of the tables. The wear limits

(2) Clean sealed ball bearings by wiping the

indicate the point at which parts may be worn

exterior surfaces with a clean cloth moistened in

before replacement, in order to assure maximum

dry-cleaning solvent. Compressed air must never

service and minimum replacement. Normally all

be used in cleaning or drying of ball or needle

bearings. Damage to bearings will result from

parts which have not worn beyond dimensions

s h o w n in the "Wear limits" columns or are

spinning of bearing by air blast.

damaged from corrosion, will be approved for

(3) Refer to TM 9-214 for information on

service.

inspection, care, and maintenance of bearings.

T h e reconditioning of

f. Painted Parts.

( 1 ) Symbols employed in the Overhaul

painted parts should be a matter of good

Standards Tables are identified as follows:

judgment. P a r t s that appear to be in good

condition after cleaning, need not be stripped

*-An asterisk in the "Wear limits" column

and repainted in their entirety, but should be

cleaned and designated for touch-up only. Parts

indicates that part must be replaced

when worn beyond the limits given in

that are rusted, or otherwise devoid of paint,

the " S i z e s a n d f i t s o f n e w p a r t s "

must be stripped to bare metal. Rubber com-

column.

p o s i t i o n shroud seals must be removed and

L-The letter "L", following the tolerance

discarded before the parts can be stripped of

dimensions given in the "Sizes and fits

paint.

of new parts" column and the "Wear

Inspection

6-3.

limits" c o l u m n , indicates a loose fit

a. General. The engines are precision built,

(clearance).

and the overhaul standards tables listed in this

T-The letter "T", following the tolerance

chapter have been fixed at extremely close limits.

dimensions given in the "Sizes and fits

The following general instructions apply to all

of new parts" column and the "Wear

inspection procedures.

limits" c o l u m n , indicates a tight fit

(1) Use modern methods and equipment

(interference).

s u c h as magnaflux, zyglo and ultrasonic in-

spection for inspecting component parts where

(2) The following is a check list of parts to

cracks and other damage cannot be detected

be magnetic-particle or flourescent-penetrant

visually.

inspected:

(2) Extreme care must be exercised in all

phases of inspection. Inspect components

following instructions in paragraph b.

6-2