bearing cap with the capscrews (2) and lockwashers (3),
near open flame or excessive heat.
tightening them evenly in increments until all are secure.
Flash point of solvent is 100 F. to
138 F. (38 C. to 59 C.).
(5) If the pump is to be mounted onto the
engine immediately, it is easier to first mount the
(3) Clean all remaining parts with cleaning
assembled bearing housing onto the engine, and then
solvent (Fed. Spec. P-D-680); dry thoroughly.
assemble the remaining pump parts to the bearing
If pump assembly is to be assembled
(4) Inspect the ball bearings for scored balls
completely for later mounting onto the engine, proceed
or races, cracked races, signs of overheating, and
as directed in steps (6) and (7) below.
binding operation; replace damaged bearings.
(6) Reassemble the centrifugal pump on the
(5) Inspect the impeller shaft for distortion,
bearing housing (para 5-3).
worn or damaged bearing seats, and damaged retaining
ring grooves, keyways, and threads. You can clean up
(7) Install the assembled pump and bearing
damaged retaining ring grooves or keyways with a fine
housing on the engine and chassis (para 2-9).
stone. Repair damaged threads with a thread chaser.
Replace the shaft if it is damaged beyond repair.
5-5. Pump Performance Test
(6) Inspect the bearing housing for cracks,
After the centrifugal pump has been repaired or
distortion, and scored or burred bearing seats. Remove
overhauled, connect the pump into a petroleum products
nicks or burrs from the bearing seats with a fine stone.
pump flow test setup to check pump output. Provide
Clean up damaged threads with a thread die. Replace a
adequate supply and discharge facilities. Install a
damaged bearing housing.
flowmeter in the discharge line. Fill the pump body with
With the engine warmed up and
c. Reassembly. Reassemble the bearing housing
operating at 2600 rpm, the centrifugal pump must meet
assembly by reversing the disassembly sequence.
the following performance requirements:
Refer to figure 5-2. Note. the following:
a. The pump shall prime in not more than 1
(1) Press bearings (8 and 10, fig. 5-2) onto
minute when subjected to a static suction lift equivalent
the impeller shaft (11). If bearings slide onto the shaft
to 10 feet using 15 feet of suction line and one elbow.
by hand, they are too loose and the bearings and/or
shaft must be replaced. Secure bearings to the shaft
b. The pump shall deliver not less than 980 to
with retaining rings (7 and 9).
1000 GPM at 60 feet total head.
(2) Press grease seal (12) into the bearing
c. After conducting tests a and b above, test the
housing (13) and grease seal (5) into the bearing cap (4)
pump check valve. Shut off the pump and allow it to set
before installing the shaft and bearings in the bearing
for not less than 30 minutes. Restart the pump and
determine if the pump immediately primes. Immediate
prime is an indication that the valve prevents siphoning
(3) Pack the bearings and bearing cap with
of fluid from the pump case and is, therefore, in good
MIL-G-10924 grease; pack the area between the
bearings in the bearing housing three-fourths full of the
d. Check the suction and pressure gages against
master gages to verify their accuracy. Output gage
(4) Press the shaft and assembled bearings
reading must correspond with master gage readings to
into the housing until the bearings are seated. Install the
within 5 percent of scale reading.
preformed packing (6) and bearing cap (4). Secure the