MR−05740
PA SERIES PUMPS
MAINTENANCE & REPAIR
PAGE C − 13
Remove the hardware securing the drive flange (9,
Figure 5) to the guard (not shown, motor driven
units only) or bellhousing (engine driven units). On
electric motor driven units, remove the coupling
guard and separate the coupling halves.
Pull the pump end straight away from the power
source. Remove the coupling half from the impeller
shaft (motor driven units).
(Engine Driven Units, Figure C−6)
As the assemblies separate, the flexible portion of
the coupling assembly (1) will remain on the shaft.
To remove the coupling from the shaft, unscrew the
two allen head setscrews from the bushing (2).
Screw one of the setscrews into the puller hole on
the circumference of the bushing. As the coupling
and bushing separate, remove the bushing, and
slide the coupling off the shaft. Remove the shaft
key (3).
It is not necessary to remove the outer ring of the
coupling from the engine flywheel unless the cou-
pling must be replaced. To remove the ring, disen-
gage the hardware (6 and 7) securing it to the fly-
wheel.
Move the pump end to a clean, well equipped shop
area for further disassembly.
Draining Oil From Seal Cavity
(Figure C−4)
If any further disassembly is to be performed on the
pump, the seal cavity oil must be drained to pre-
vent the oil in the seal cavity from escaping as the
pump casing is removed.
Position a large (3 gallon [11,4 liter] minimum),
clean
container under the seal cavity drain plug
(12). Remove the drain plug and drain the oil from
the seal cavity into the container. Clean and rein-
stall the drain plug. Inspect the oil for water, dirt or a
cloudy condition which could indicate seal failure.
Loosening Impeller
(Figures C−5 and C−7)
With the pump end separated from the engine, in-
sert a block of wood through the pump discharge
and wedge it between the vanes of the impeller
and the pump casing to prevent rotation. Remove
the impeller capscrew and washer (21 and 22).
Install the shaft key (10) in the shaft keyway. Install
a lathe dog on the drive end of the shaft (11) with
the V" notch positioned over the shaft key.
With the impeller rotation still blocked, see Figure
C−7 and use a long piece of heavy bar stock to pry
against the arm of the lathe dog in a counterclock-
wise direction (when facing the drive end of the
shaft).
Use caution
not to damage the shaft or key-
way. When the impeller breaks loose, remove the
lathe dog, key and wood block.
NOTE
Do not remove the impeller until the rotating assem-
bly has been removed from the pump casing.
Turn
Counterclockwise
Lathe Dog Arm
V" Notch
Shaft Key
Impeller Shaft
Lathe Dog
Setscrew
Heavy
Bar Stock
Figure C−7. Loosening Impeller
Pump Casing Removal
(Figure C−4)
Support the pump casing using a suitable hoist
and sling, and remove the hardware (9 and 10).
Install four 1/2−13 UNC x 2-inch long jacking
screws in the tapped holes in the bearing housing
(4, Figure C−5). Tighten the jacking screws in an
alternating pattern until the pump casing is pushed
off of the bearing housing. Remove the jacking
screws.
