TM 10-4320-344-24
3.6.7 Impeller Maintenance. (Continued)
Ensure chamfer of spring centering washer faces towards spring.
f .
Install spring (4) and seal washer (3) on impeller shaft (7).
g .
Install impeller adjusting shims (2), if any were present.
h .
Install impeller (1) on impeller shaft.
i .
Apply antisieze sealing compound to cap screw (Figure 3-8, 6) and install
sleeve spacer (7) and cap screw (6).
j .
Install bar (5) between two bolts (4) and torque cap screw (6) to 90 ft-lbs
(122 N•m).
Maximum allowable impeller shaft end play is 0.002 (0.051 mm) to 0.010 inches
(0.254 mm).
k.
Using vernier calipers, center impeller (Figure 3-10, 1) in volute scroll (2)
a s f o l l o w s:
1)
Measure distance across narrowest point of volute channel.
Write down HALF
of measurement (Dimension A).
2)
Measure distance from engine side of narrowest point of volute channel to
back of volute gasket.
Ensure gasket is flush against face of volute
c a s i n g.
Write down measurement (Dimension B).
3)
Add Dimension A and Dimension B (Dimension AB).
4)
Measure distance between faces of inner and outer shrouds of impeller (1).
Write down HALF of measurement (Dimension C).
When measuring face of seal plate to rear shroud of impeller, make sure
impeller shaft is horizontal.
Because of ball bearing play of 0.20 inches
(5.08 mm), impeller shaft may tilt slightly.
5)
Measure distance from face of seal plate to rear shroud of impeller (1).
Write down measurement (Dimension D).
6)
Add Dimension C and Dimension D (Dimension CD).
7)
Subtract Dimension CD from Dimension AB.
This value gives correct
thickness of impeller adjusting shims (Figure 3-9, 2) required to center
impeller (Figure 3-10, 1) in volute scroll (2).
8)
Remove impeller (1) and measure thickness of installed impeller shims
(Figure 3-9, 2).
Add or remove shims (2), as necessary, to reach correct
thickness and center impeller (1) in volute scroll (2).
9)
I n s t a l l i m p e l l e r ( 1 ), refer to steps h through j.
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