Section VIII. OVERHAUL INSTRUCTIONS

3-22. GENERAL

b r a c k e t with its assembled impeller shaft (44),

bearing (48), and seal (46). Pull straight out on

T h i s section provides information useful for repair

t h e bracket so that the splines of the impeller

and replacement of pump components. Detailed repair

s h a f t will disengage the splined coupling (53)

information for the engine is provided in the engine

secured to the engine.

manual. TM 5-2805-259-14.

(7) R e m o v e the retaining ring (43) and push the

3-23. CENTRIFUGAL PUMP

a s s e m b l e d impeller shaft (44) and bearing (48)

from the intermediate bracket (42). The bearing

--. D i s a s s e m b l y .

retainer (45) and its assembled oil seal (46) will

b e released as the shaft is removed from the

W a r n i n g . Always disconnect spark plug leads from

bracket. Remove the oil seal (50) from the

spark plugs before starting disassembly

intermediate bracket after the shaft assembly is

procedures. This will prevent engine from

removed.

s t a r t i n g accidentally during disassembly.

(8) Remove the two retaining rings (47 and 49) and

D i s a s s e m b l e and remove the pump, following the

p r e s s the shaft (44) from the bearing (48). .

s e q u e n c e of the key index numbers assigned to the

(9) Remove the four capscrews (51) and lockwashers

exploded view in figure 3-13. Give particular attention

to the following:

(52) that secure the splined coupling (53) to the

engine. Do not remove the pilot bushing from the

(1) Before beginning disassembly:

c o u p l i n g unless it is damaged and requires re-

placement.

(a) Drain volute casing (fig. 3-11).

b . Cleaning. Clean all parts in an approved solvent

and blow dry with clean, dry compressed air.

(b) Remove exhaust primer connection from priming

tube (16).

c . Inspection and Repair.

( c ) Remove the attaching parts which secure the

(1) I n s p e c t a l l p a r t s f o r w e a r , c r a c k s , s c o r i n g ,

support bracket (25) to the skid.

and other damage. Replace all gaskets and seals,

and all other parts found to be defective.

(2) W h e n volute casing (21) and assembled parts

are removed, impeller (27) and intermediate

(2) Check the condition of the wear rings (28 and 35)

bracket (42) will remain mounted on the engine.

pressed into the volute casing (21) and seal

p l a t e (32). The internal diameter of the rings

(3) A r i g h t - h a n d t h r e a d s e c u r e s i m p e l l e r ( 2 7 ) t o

should not exceed 0.070 inch more than the

impeller shaft (44). To remove the impeller from

e x t e r n a l diameter of the mating portion of the

the impeller shaft, hold the engine starter pulley

impeller. If worn or damaged, lay the assembly

a n d turn the impeller counterclockwise facing

on a flat surface and block firmly. Using a sharp

impeller end.

chisel, remove the bronze wear rings. Press new

r i n g s into place until they are fully seated. If

(4) After the removal of the impeller, the shims (28),

t h e internal diameter of the new wear ring is

s e a l spring, and seal rotating element can be

0.070 inch greater than the mating external

removed from the impeller shaft (44). The shaft

d i a m e t e r of the old impeller, replace the im-

sleeve (34) can also be removed.

peller.

(5) Remove the eight nuts (29) and lockwashers (30)

(3) I n s p e c t the ball bearing for cracked or scored

that secure the seal plate (32) to the intermediate

races, pitted or scored balls, and signs of over-

bracket (42) of the pump; remove the seal plate

heating. Rotate the races by hand and check for

and its assembled wear ring (35), and stationary

r o u g h , catching, o r b i n d i n g o p e r a t i o n . T h e r e

ring of the seal assembly. Remove the stationary

s h o u l d be no more than just perceptible play

ring and its assembled O-ring from the seal

between the balls and races.

plate.

(6) R e m o v e the eight capscrews (36 and 38) and

(4) It is good practice to replace the shaft seal with

l o c k w a s h e r s (37 and 39) that secure the inter-

every overhaul. Replace the seal as a complete

mediate bracket (42) and guard (40) to the

assembly. Do not mix new and used parts.

engine; remove the guard and intermediate

3-13