MR−05740
PA SERIES PUMPS
MAINTENANCE & REPAIR
PAGE C − 19
er substance which may soften or otherwise dam-
age the rubber.
If removed, install the guards (27, Figure C−5),
and secure the drive flange to the engine bellhous-
ing with the previously removed hardware (8 and
9).
(Electric Motor Driven Units Only, Not Shown)
Install the coupling half on the impeller shaft. Using
a suitable lifting device, position the pump end as-
sembly on the base. Align the coupling halves and
reinstall the attaching hardware. Install the cou-
pling guard and secure the drive flange to the
guard with the previously removed hardware.
Wear Plate And Back Cover Plate Installation
And Adjustment
(Figures C−4 and C−9)
If the wear plate (5) was removed for replacement,
carefully center it on the back cover (15) and se-
cure it with the hardware (3 and 4).
Lubricate the O-rings (6 and 14) with light grease
and install them in the grooves in the wear plate
and back cover.
Clearance between the impeller and wear plate is
adjusted using four hand knobs (19) and locking
collars (17). There are 18 detents on the I.D. of
each locking collar. Indexing the collars one detent
on the adjusting screws represents approximately
.005 inch (0,13 mm) of wear plate clearance. The
recommended clearance between the wear plate
and the impeller is .010 to .020 inch (0,25 to 0,50
mm).
USE TWO
OPPOSING
HAND NUTS
TO PRESS
BACK COVER
INTO PUMP
CASING
USE TWO REMAINING
ADJUSTING SCREWS
AND LOCKING COL-
LARS TO SET FACE
CLEARANCE
INDEX COLLARS 3
DETENTS COUNTER-
CLOCKWISE, THEN
TURN CLOCKWISE
UNTIL SCREW HOLES
ALIGN
Figure C−9. Installing and Adjusting Back
Cover
Screw the four adjusting screws (16) into the
tapped holes in the back cover plate until they are
just flush
with the machined surface on the back
side of the cover plate.
Align the back cover plate over the studs (18) and
slide it into the pump casing. Use two hand knobs
(19) on diagonally opposing studs to press the
back cover into the pump casing until the wear
plate
just touches
the impeller when the shaft is
turned by hand.
Tighten the hand knobs evenly
to avoid binding.
With the wear plate just touching the impeller, turn
the two free adjusting screws until they engage the
pump casing. Position the locking collars over the
adjusting screws so the holes in the collars for the
locking screws align approximately with the holes
in the cover plate.
Loosen the hand knobs used to press the back
cover into the pump casing one full turn.
Pull the collars off the adjusting screws, index them
three detents counterclockwise, and reinstall the
collars on the adjusting screws. Use the collars to
turn the adjusting screws clockwise until the holes
in the locking collars realign with the tapped screw
holes in the back cover plate. Secure the locking
