TM 9-2330-356-14
(b) Then remove enough shims to move the
WARNING
impeller away from the wear plate a distance of 0.015-inch.
Be careful when removing the Impeller from
(c) Rotate the pump by hand to make sure
the pump. The spring load on the mechanical
the impeller is not binding or scraping.
seal may cause the impeller to fly off the shaft
as it is being removed, causing serious injury
(d) Minor nicks on edges of impeller vanes
to personnnel.
can be removed by finishing with a fine stone.
(e) If the impeller and wear plates are worn
(c) Apply force to strap wrench in a
excessively, they must be replaced.
count counterclockwise direction. Using a block of hard wood
and a hammer, hit the hub of impeller to loosen it on the
(f) After replacement of the impeller, wear
shaft. Remove the impeller by unscrewing it from the
plate, or impeller shaft, check for clearance between the
impeller shaft.
BACK of the impeller and the seal plate. If the impeller
scrapes when the seal plate (15) is installed, add another
(4) Pull the seal plate (15) and the mechanical
gasket (19) of sufficient thickness between the seal plate
seal (16) from the impeller shaft.
and the pump casing.
(2) Mechanical Seal (16). Inspect the mating
(13) from bearing cap (11). Remove the bearing cap and
surfaces of the seal for wear, scoring, grooves or other
discard gasket (10).
damage which can cause leakage. If any of the seal parts
are worn, replace the entire seal. Never mix old and new
(6) Remove pump coupling (28) and key (29)
parts of a seal.
from opposite end of shaft, if these items were not already
(3) Impeller Shaft (8). Inspect the impeller shaft
removed.
for nicks, scratches, scoring or other damage. Replace the
shaft if damaged.
(7) Using a soft hammer, hit the keyed end of the
impeller shaft to remove the shaft (8), bearings (9 and 6),
(4) Bearings (6 and 9). Rotate bearings by hand
and spacer (7) from intermediate housing (3).
and check for binding or wear. Replace bearings if wear is
found. The bearings are a light press fit on the impeller
(8) Remove seal (5) from intermediate housing.
shaft and a snug push fit in the housing. If the shaft is worn
Discard the seal.
so the bearing slips on and off easily, the shaft must be
replaced. Replace the housing if the bearings do not fit
(9) Remove the seal (14) from the bearing cap
snugly into the bearing bore.
(11). Discard the seal.
(5) Gaskets and Seals. Whenever a pump is
(10) Remove snap ring (27), bearing (9), and
overhauled, ail gaskets should be replaced. However, if
bearing (6) from impeller shaft (8).
old gaskets must be reused, soak the gaskets in water to
prevent them from drying out and shrinking. Inspect all
(11) The wear plate (21) is fastened to the volute
seals carefully and replace any that are damaged.
with two nuts (25) and lockwashers (26). Remove the wear
plate only if excessive wear is evident and replacement is
necessary (step e).
(1) Install new seal (5) in bore of intermediate
d.
housing. Lip of seal must be toward the impeller.
e.
NOTE
Loading groove in bearings must be installed
(1) Impeller and Wear Plate. The open impeller
toward the shoulder or center (largest
(20) uses a wear plate (21) in front of the impeller vanes to
diameter) of the impeller shaft.
minimize internal pump leakage. This wear plate normally
receives most of the wear. Pump efficiency will decrease
considerably when the clearance between the wear plate
(2) Press bearing (9) over threaded end of
and impeller exceeds 0.035-inch. Normally, shims (18) can
impeller shaft (8) and install snap ring (27).
be added to bring clearance within limits.
(3) Put spacer (7) onto impeller shaft against
bearing just installed. Press bearing (6) with loading
(a) Add shims until rubbing just starts to
groove towards spacer onto keyed end of impeller shaft
occur when the impeller and wear plate are secured in
place.