Maintenance 7
Impeller Removal
1. Follow steps 1 through 4 under Cutting Rotor.
2. unscrew the four 5 mm capscrews holding the
volute to the seal plate and tap the volute to loosen
it. remove the volute.
NOTICE: Be sure you have the correct capscrews –
the wrong ones will release the motor housing from
the bracket and also release a lot of oil!
3. With a screwdriver (or two) behind the impeller,
work the impeller down the shaft until it is free.
remove it.
4. If the shaft key stayed in the shaft, remove it.
5. reverse steps 1 through 4 to reassemble the impeller.
torque the four capscrews to 5.9 ft-lb (8 nm).
Main Seal Replacement
1. Follow steps 1 through 4 under Cutting Rotor.
2. Follow steps 2 through 4 under Impeller Removal.
3. lay the pump on its side and remove the oil plug
from the bracket. the oil fill/oil drain opening is
labled “oHl”. drain oil into a clean container and
check for water and pollutants in the oil.
NOTICE: Water is heavier than oil. look for water at
the bottom of the oil. It will appear as tiny bubbles.
If there is water present in the oil, the shaft seal or
the o-ring will need to be replaced. If there is no
water present in the oil, the shaft seal and o-ring do
not need replacing.
4. remove the two 8 mm capscrews that hold the
motor housing to the bracket. tap around the parting
line with a lead hammer or rawhide mallet to loosen
the motor housing. remove the motor housing from
the bracket.
5. remove the oil seal and oil seal bushing from the
motor housing.
6. remove the motor housing o-ring and clean the
o-ring groove.
7. remove the seal retaining ring from the motor
housing.
NOTICE: the shaft seal consists of several parts. Be
sure that you do not scratch or mar the shaft when
removing the seals. If the shaft is marred, it must be
dressed smooth with fine emery or crocus cloth before
installing new seal. do not reduce the shaft diameter.
8. pull and turn the rotating seal halves to remove them
from the motor shaft. If necessary, use a flat blade
screwdriver to help pry the seals from the shaft.
9. unscrew four capscrews and remove the bracket
from the motor housing.
10. use a flat blade screwdriver and very carefully pry
the lower seal half from the cavity.
11. use a flat blade screwdriver and very carefully pry
the upper seal half from the bracket cavity.
Installing the New Shaft Seal
NOTICE: Install all new o-rings, seals, and gaskets
during reassembly. It is good practice to replace the
o-rings each time the pump is serviced.
1. clean the seal cavities in the bracket and
motor housing.
2. lubricate the seals with a very small amount of
clean seal chamber oil.
3. Inspect the shaft for nicks and scratches.
4. With finger pressure only, press the stationary seal
halves firmly and squarely into the seal cavities in
the bracket and motor housing.
NOTICE: Be sure you do not scratch the seal surface.
5. reinstall the lower seal retaining ring.
6. reinstall the bracket on the motor. use a new
o-ring. torque 8 mm capscrews to 14.8 ft-lb
(20 nm).
7. slide the rotating seal components onto the shaft.
NOTICE: Be sure you do not scratch the seal surface.
Be careful that the shaft shoulder does not damage
the seal faces when they are passing over the shaft.
Make certain the polished surfaces of the rotating
seals face the mating surfaces of the stationary
seal halves.
8. clean the o-ring groove in the bracket and install a
new o-ring.
NOTICE: It is good practice to replace the o-rings
each time the pump is serviced.
9. reinstall the oil seal and the oil seal bushing on
the shaft.
10. reinstall the impeller drive key in the keyway on
the shaft.
11. using the key as a guide, reinstall the impeller on
the shaft.
12. reinstall the volute on the seal plate. torque four
fasteners to 5.9 ft-lb (8 nm).
13. reinstall the cutting rotor.
14. Block the cutter with a block of wood and reinstall
the socket head capscrew. torque capscrew to
5.9 ft-lb (8 nm).
15. refill the bracket with fresh, clean oil. see Product
Specifications for specific amount.
16. stand the pump on its feet. check for free rotation of
the impeller.
the pump is ready to return to service.
