Maintenance
Ampco Pumps Company
Page 28
Ampco Pumps Company ZP3 Manual M-004 Rev A 10.15
Gear Case Maintenance
2)
Single ball bearings are used for the rear bearings in models ZP3 6, ZP3 15, ZP3 18, ZP3
30, and ZP3 34 and will require a light press to install. Tapered roller bearings are used for all
other models and will be pressed on similar to the front bearings.
For pump models with single ball bearings apply a light coat of lubricant on the
shaft. Open the new rear bearing assembly and place it over the shaft above the
bearing spacer with the shielded side of the bearing facing the spacer (Figure 52,
Drawing 1). Press the bearing on by pressing only on the inner race.
For pump models with tapered roller bearings, apply a light coat of lubricant on the
shaft. Open the new rear bearing assembly and do not interchange any parts.
Place the rear bearing over the shaft above the bearing spacer (Figure 52, Drawing
2). Reference Table 7, page 27 for the required force (in tons) needed to press the
bearing onto the shaft. Using a sleeve that rests on the inner cone of the bearing
and rides over the shaft, press the bearing on until it seats against the spacer.
Make sure the bearing is rested on the bearing spacer using a shim (Figure 52, Drawing 3).
Figure 52: Pressing Rear Bearing onto Shaft
3)
Shims located on the shaft, behind the front bearing, control the backface clearance of the
pump; the space between the body and the rotor. If neither the shafts nor bearings are being
replaced, use the shims (if properly marked) removed at disassembly and reuse making sure
they are installed in the correct bores. If replacing shafts or bearings, a process of calculating
the required shims is necessary. Use Figure 53 and the following equation to calculate. To
find the correct backface clearance see Table 4, page 22.
Figure 53: Calculating Shims
Drawing 1
Drawing 3
Drawing 2
Check Seat
With Shim
A
D
B
C
Shim
Thickness
Gear Case
Shaft
Body
Measure A, B, C, and D
Find Correct Backface Clearance
Backface ClC+A-D-B=
Shim Thickness
A:
Body Width
B:
Depth of Rotor Bore
C:
Distance from gear case pads to
bottom of front bearing pocket
D:
Distance from shaft shoulder to
back of bearing race
