Maintenance
Waukesha Cherry-Burrell
®
Brand Universal 3 Pump
Page 30
95-03103
02/2021
Inspection of Gears and Bearings
Gear backlash
With the fluid head and seals removed, feel for gear backlash by
rotating either shaft by hand. The other shaft must engage imme-
diately. Perform this check three times at 60-degree intervals. If
play (backlash) is evident, remove the gear case cover, check the
gear teeth for wear, and ensure that the gear is not loose on the
shaft. If the gear teeth are worn, replace the gears. If the gear is
loose on the shaft, inspect the shaft key and keyway; replace as
necessary.
Check bearing condition
With the fluid head and seals removed, check the bearing condi-
tion by applying (by hand) an up or down force of approximately
30 lbs (14 kg). If movement is detected, the bearing may be fail-
ing. Also check the shaft movement forward or backward. If the
bearing is failing, replace the bearing and review the lubrication
section starting on page 28.
Annual Maintenance
DANGER
The pump contains internal moving parts. DO NOT put hands or
fingers into the pump body ports or drive area at any time during
operation. To avoid serious injury, DO NOT install, clean, service,
or repair the pump unless all power is off and locked out and the
pump is de-pressurized.Shut off and drain product from the pump
prior to disconnecting the piping.
At least annually, perform the procedures and corrective mea-
sures outlined in “Maintenance Inspections” on page 29, in addi-
tion to the following preventive maintenance:
•
Check the bearings with a dial indicator for shaft radial play. If
the deflection is equal to or greater than the rotor-to-body
diametrical clearance (see “Checking for Proper Clearance”
on page 88), replace the bearings.
•
Remove the gear case cover and inspect the gears for wear,
backlash and looseness. Loosen and torque the gear
retaining nuts to the proper torque.
•
Thoroughly inspect the rotors for worn splines, hub wear and
stress cracks (see arrows in Figure 35). Use the dye check
method to detect any fatigue-type cracks at rotor stress
points.
•
Review the performance record on the pump, and check the
radial and backface clearances to determine wear and effect
on performance. Adjustment to the operating speed can
compensate for wear in some applications.
CAUTION
When bearings or shafts are replaced in the field, take care to
correctly position the shaft by shimming it to maintain sufficient
running clearances between the rotor wing faces and the pump
body faces (backface and cover face). It is important to hold the
same backface dimension for both rotors, within 0.0005” (0.0127
mm), to avoid crossover interference.
Figure 33 - Backlash Check
Figure 34 - Bearing Deflection Check
PD100-639
PD100-640
Figure 35 - Rotor Stress Points
PD100-651