Waukesha Cherry-Burrell
®
Brand Universal 3 Pump
Maintenance
02/2021
95-03103
Page 85
Shimming
1. When installing the shafts in the gear case, shim behind the
front bearing to achieve the proper backface clearance
between the back of the rotors and the body. (See Figure
207.) The backface clearance must be equal for both rotors
to prevent the rotors from hitting each other during operation.
NOTE:
Do not install bearing retainer sealant, gears, or gear
locknuts until the correct shimming has been verified.
2.
If the shafts and/or bearings do not need to be replaced
and
the
shims are marked indicating the shaft and
bearing they are matched with,
a shim adjustment probably
will not be necessary. Reuse the existing tagged shims,
shafts and bearings in the same gear case bores.
3.
If existing shims are lost and/or a standard shaft is used,
determine the required shims from the chart.
4.
If it is necessary to calculate the required shims for
replacement shafts, bearings or both,
refer to Figure 207
and Figure 208; carry measurements and calculations to
three decimal places (e.g. 0.059).
5. Determine the shim thickness required for the front bearing:
•
Measure “B” in the gear case and “C” on the shaft (Figure
207).
NOTE:
Arrange with thicker shims on
outside of the shim pack.
•
Measure “D” and “E” on the body (Figure 208).
•
Determine the proper backface clearance. Refer to
Table 18, “Rotor Clearances,” on page 89.
•
Required Shims = Backface clearance - C + B + D - E.
6. Place the shims in the gear case, resting against the shoulder
in the front bearing bore. (See Figure 207.)
Figure 207 - Measure B & C
Figure 208 - Measure D & E
B. Front face of gear case to back of
bearing bore
C. Shaft shoulder to back of bearing race
D. Body thickness
E. Depth of rotor cavity
B
C
PD100-655
Gear case
front face
Shim
location
D
E
Body
CAUTION
Make sure the pump is securely bolted or clamped down prior to
performing any maintenance work. The pump center of gravity
changes as parts are added or removed, and could result in
tipping of an unsecured pump.
Suggested Shims
U3 Model
Standard Shaft
Replacement
Shaft
Shim kit
006, 014, 015, 018
.113 in (2.87 mm) .110 in (2.79 mm)
030, 034, 040
.105 in (2.27 mm) .102 in (2.59 mm)
045, 060, 064,
130, 134
.093 in (2.36 mm) .088 in (2.24 mm)
180, 184, 220, 224
.115 in (2.92 mm) .110 in (2.79 mm)
210, 214, 320, 324
.125 in (3.18 mm) .120 in (3.05 mm)