OM-06622
PA SERIES
MAINTENANCE & REPAIR
PAGE E - 23
and 21). Install the two remaining back cover nuts
snugly against the adjusting screws.
Remove the first two back cover nuts from their
studs. Turn the adjusting screws clockwise until
they engage the pump casing. Install the locking
collars (20) and hardware (11 and 21). Reinstall the
back cover nuts.
Be sure the wear plate does not scrape against the
impeller.
Over time it may be necessary to repeat the adjust
ment process to compensate for normal wear be
tween the impeller and wear plate. When all of the
adjustment has been used on the suction spool
side of the pump, an additional 0.120 inch (3 mm)
of adjustment may be obtained by removing the ro
tating assembly adjusting shims (26).
Allow an installed pump to completely cool before
draining liquid from the pump casing. Remove the
suction spool. Remove the rotating assembly ad
justing shims, then reinstall the hardware securing
the rotating assembly to the pump casing. Perform
the back cover adjustment procedure described
above to obtain the proper face clearance.
Be sure the wear plate does not scrape against the
impeller.
Over time it may be necessary to repeat the adjust
ment process to compensate for normal wear be
tween the impeller and wear plate. When all of the
adjustment has been used on the back cover side
of the pump, an additional 0.120 inch (3 mm) of ad
justment may be obtained by removing the rotat
ing assembly adjusting shims (17).
Allow an installed pump to completely cool before
draining liquid from the pump casing. Remove the
back cover. Remove the rotating assembly adjust
ing shims, then reinstall the hardware securing the
rotating assembly to the pump casing. Perform the
back cover adjustment procedure described
above to obtain the proper face clearance.
Pump Casing Installation
(Figure 4)
Lubricate the rotating assembly O‐rings (6 and 8)
with a light coating of grease. Use a suitable hoist
and sling to slide the pump casing (1) over the ro
tating assembly until the wear plate touches the im
peller.
Measure the gap between the wear plate and the
impeller at several locations. This gap should be
between .010 to .012 inch (0,25 and 0,3 mm).
When this gap is established, assemble the shims
(26) into sets thick enough to fill the gap between
the bearing housing and the pump casing at the
points for the mounting hardware (10 and 11A).
Install the shims and secure the bearing housing to
the pump casing with the hardware (10 and 11A).
Check the impeller‐to‐wear plate clearance and
add or remove adjusting shims as required to
achieve the correct clearance.
Securing Pump And Drive Assembly To Engine
(Figure 8)
Install the shaft key (23, Figure 5) in the shaft key
way. Position the flexible portion of the coupling as
sembly (1) on the shaft as shown in Figure 8.
NOTE
The flexible portion of the coupling must be proper
ly positioned on the shaft. The heads of the caps
crews in the center of the coupling
must be posi
tioned away from the pump end of the shaft
.
Align the keyway in the bushing (2) with the shaft
key, and slide it onto the shaft to the dimension
shown in Figure 8. Rotate the flexible portion of the
coupling until the tapped holes for the two set
screws align with those in the bushing, and install
the setscrews.
Make certain that the flexible portion of the
coupling is mounted as shown in Figure 8.
This is critical.
If the coupling is not prop
erly positioned on the shaft, the coupling
parts may not fully engage, or a pre‐load
condition can cause premature bearing
failure.
The coupling must be positioned 1.44
inches (37 mm) from the end of the shaft.
This will allow the two portions of the cou
pling to fully engage when the drive flange