2-19. lMPELLER-lNSPECT/REPAIR (Cont)
Use an outside caliper to inspect impeller height,
dimension A. If impeller height is less than 0.585
inch (14,85 mm), replace impeller.
Visually inspect leading edges of impeller fins.
Leading edges should be sharp. A small amount of
chipping on leading edges is acceptable. Replace
impeller if fin edges are blunt or damaged.
If key-drive type impeller is being
inspected, inspect drive boss per Step e
below. Key-drive type impeller and
armature are obsolete. If key-drive type
impeller is defective, both impeller and
armature must be replaced.
d. Visually check impeller D-drive. If flat edge of
D is curved or deformed, replace impeller.
Measure impeller key slot width, dimension C.
Using a feeler gage, take measurement at inside
edge of slot near the shaft bore. If key slot width
exceeds 0.067 inch (1,70 mm), replace both arma-
ture and impeller. The key slot width can also be
checked with a No. 50 drill. If shank of a No. 50
drill can be inserted into key slot, impeller slot is
worn. Replace both impeller and armature.
f. Inspect impeller seal face surface for wear. If sur-
face is worn dull or grooved, lap impeller as
instructed in REPAIR procedures.
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