11.5
Replacing Crankshaft Journal Bearings and Connecting Rods
1)
Remove the access panels per
Section 11.3
.
2)
Working through the rear cover opening, remove the hex screws connecting the rod to the crosshead
pin using a 3/16" hex socket wrench with a universal knuckle and extension. In order to access each
of the four screws per rod, rotate the crankshaft until screws are accessible.
3)
There are two dowel pins that align the crosshead pin to the connecting rod. With screws removed,
support the end of the rod at the crosshead and push the crosshead forward to disengage the dowel
pins. If the rod does not easily release from the crosshead pin the crosshead may be tapped from the
back of the pump or pried forward through the side access window. Block one of the other
crossheads before doing this to prevent the crankshaft from rotating.
4)
Use pliers to remove the 1/8" cotter pins from the connecting rod bolts. Discard the cotter pins, they
are not intended for reuse and must be replaced after removal.
5)
Using a 15/16" wrench, remove each of the four 5/8" castellated nuts and bolts from each connecting
rod.
NOTE: Each connecting rod and cap is matched. It is extremely important that they be keep together at
all times. Perform the following steps one rod at a time to prevent potential for mismatch during
reassembly. Assembling with mismatched rods and caps may result in severe damage to the pump. See
specific installation torques in
Appendix C
for reinstallation of rod cap.
6)
Support the cap of the connecting rod and gently tap it from both ends using a brass punch to
disengage the dowel pins. Be extremely careful not to mar the journal surface of the crankshaft.
7)
Push the connecting rod forward to disengage it from the crankshaft. Rotate the crankshaft until the
rod can be removed from beneath the journal. Inspect the shell bearing for signs of scoring, pitting,
spalling, or excessive heat. If the backing material is visible the bearing must be replaced. It is
critical that bearings always are replaced as a set.
8)
The connecting rod journal bearings have tangs that mate to recesses in the connecting rod. It is
imperative that these tangs be oriented such that they prevent rotation within the connecting rod
during operation. See drawing on following page for more information.
If the journal bearings are to be reused they must be reinstalled in the exact connecting rod piece they were
removed from, keeping items marked during disassembly is important to prevent mismatch.
The connecting rods retain the crosshead pins and prevent the crossheads from rotating inside their bore. Be
aware that once the connecting rods are removed the crosshead could rotate and allow the crosshead pin to fall
out of the bore. Care should be taken during disassembly to prevent this from occurring.
11.6
Replacing Crosshead, Crosshead Pins and Crosshead Bushings
1)
Remove the fluid end plungers per instructions in
Section 9.2
.
2)
Remove the access panels per
Section 11.3
.
3)
Remove the power end plungers and seal housings per instructions in
Section 11.4
.
Revision K 03/12/2019
MSI - A Division of Dixie Iron Works, Ltd. All rights reserved.
Page 72