Gorman-Rupp Pumps 12B20-B 1340494 and up - Manual (Page 28)

OM-00588 10 SERIES
MAINTENANCE & REPAIR PAGE E - 5
Pump Casing Removal
Death or serious personal injury and
damage to the pump or components
can occur if proper lifting procedures
are not observed. Make certain that
hoists, chains, slings or cables are in
good working condition and of suffi­
cient capacity and that they are posi­
tioned so that loads will be balanced
and the pump or components will not be
damaged when lifting. Suction and dis­
charge hoses and piping must be re­
moved from the pump before lifting. Lift
the pump or component only as high as
necessary and keep personnel away
from suspended objects.
To service the impeller or seal assembly, discon­
nect the discharge piping. Remove the hardware
securing the pump to the base.
Remove the nuts (30) and separate the pump cas­
ing and gasket set (31) from the seal plate (32) and
pedestal (22). Tie and tag the casing gaskets, or
measure and record their thickness for ease of
reassembly.
Clean the mating surfaces of the seal plate and
pump casing.
Tie and tag any leveling shims used under the
pump casing mounting feet to ease reassembly.
Impeller Removal
Before removing the impeller, remove the bottle oil­
er and piping (59, 60 and 61). Remove the air vent
and piping (6, 7 and 8). Remove the seal cavity
drain plug (28) and drain the cavity to prevent the
oil from escaping when the impeller is removed.
Clean and reinstall the drain plug.
Disconnect the power source.
Immobilize the impeller by wedging a block wood
between the vanes. If removed, install the shaft key
(17). Install a lathe dog on the drive end of the shaft
(19) with the “V” notch positioned over the shaft
keyway.
With the impeller rotation still blocked, use a long
piece of heavy bar stock to pry against the arm of
the lathe dog in a counterclockwise direction
(when facing the drive end of the shaft) as shown in
Figure E-2. Use caution not to damage the shaft
or keyway. When the impeller breaks loose, re­
move the lathe dog and wood block.
Turn
Counterclockwise
Lathe Dog Arm
“V” Notch
Shaft Key
Impeller Shaft
Lathe Dog
Setscrew
Heavy
Bar Stock
Figure E-2. Loosening Impeller
Unscrew the impeller from the shaft. Use caution
when removing the impeller; tension on the seal
spring will be released as the impeller is un­
screwed.
Inspect the impeller and replace it if cracked or
badly worn. Slide the impeller adjusting shims (5)
off the impeller shaft. Tie and tag the shims or mea­
sure and record their thickness for ease of reas­
sembly.
Seal Removal and Disassembly
Remove the spring centering washer and seal
spring. Slide the shaft sleeve (4) and rotating por­
tion of the seal off the shaft as a single unit. Apply oil
to the sleeve and work it up under the bellows.
Slide the rotating portion of the seal off the sleeve.
Slide the seal plate and stationary portion of the
seal assembly off the shaft as a unit. Position the
seal plate on a flat surface with the impeller side
down. Use a suitably sized dowel to press the seal
stationary components from the seal plate bore.