INSPECT COMPRESSOR WHEEL AND NUT

TM 9-2990-206-34&P

INSPECTION-Continued.

TOOLS:

0.3125 to 0.5000 inch telescope gage

O.(X) to 1.00 inch micometer

1. Inspect compressor wheel nut (A) for thread damage

or deformation.

CAUTION

Cracked compressor wheel blades will break

during operation and-cause failure..

2. Inspect compressor wheel (B) for cracked, broken, bent,

eroded, or missing blades. Inspect rear surface of

compressor wheel for evidence of wear or scoring.

3. Measure and record compressor wheel bore diameter

4. Replace dammed comressor wheel nut. Replace com-

pressor wheel if damaged, or if bore diameter ex-

ceeds 0.3739 inch (9.497 mm).

INSPECT BACKPLATE

TOOLS:

0.5000 to 0.7500 Inch telescope gage

0.00 to 1.00 inch micrometer

1. Inspect backplate (D) for cracks. Inspect mounting flange

and machined mating surface for distortion or warpage.

2. Flush oil hole with solvent. Solvent must enter

through hole (E) and flow freely through three holes (F).

3. Inspect thrust bearing (G) for evidence of overheating,

scoring, or looseness. The three thrust bearing pads

(H) must be smooth and flat. All three pads (H) must be

parallel to surface (J) within 0.0010 Inch (0.025 mm).

Surface (J) flatness must not exceed 0.0005 inch total

indicator reading (TIR) (0.0127 mm TIR).

4. Inspect bore (K) for scratches or scoring. Measure bore

diameter (K) using telescope gage and micrometer. Re-

place backplate If bore diameter exceeds 0.6885 inch

(17.49 mm).

5. Measure depth from surface (J) to thrust bearing pad (L).

Replace backplate if depth exceeds 0.3980 inch 10.11 mm).

6. Replace backplate if cracked, distorted, or does not meet

TA097818

wear limit requirements.

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