INSPECT SHROUD

TM 9-2990-206-34&P

INSPECTION-Continued.

INSPECT SHROUD

Inspect shroud (A) for cracks, nicks, and

raised metal.

2. Inspect mating flange for distortion. Inspect flat

face of shroud for evidence of rubbing or scoring

from the turbine wheel.

3. Replace damaged shroud.

INSPECT TURBINE WHEEL

TOOLS:

0.00 to 1.00 inch micrometer

0.0015 to O.025 inch blade thickness gage (feeler)

CAUTION

Cracked turbine wheel blades will break

during operation and cause failure.

Inspect turbine wheel (B) for cracked, broken, bent,

eroded, or missing blades. Inspect shaft for cracks,

scratches, or scoring. Inspect bearing journals and

threads for damage. Inspect rear surface of turbine

wheel for evidence of wear or scoring. Inspect

seal ring groove (C) for wear.

Inspect blade tips for feather-edge or tears.

Measure blade tips (D) with micrometer. Replace

turbine wheel if damaged, or if blade thickness is

less than 0.025 inch (0.635 mm).

Measure seal ring groove (C) width and diameter

using thickness gage and vernier calipers. Replace

turbine wheel if groove width exceeds 0.0685 inch

(1.7399mm) or groove diameter is less than 0.8600

inch (21.84 mm).

Measure shaft bearing journals (E) using micrometer.

Replace turbine wheel if diameters are less than

0.6250 inch (15.875 mm).

Measure shaft hub diameter (F) using micrometer.

Replace turbine wheel if diameter is less than

0.9950 inch (25.273 mm).

TA097821

3-15