Lull 944E-42 Service Manual - Manual (Page 421)

8.169 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
13. Remove the square cross section o-ring (18) from
the ported section (14). Discard the o-ring.
14. Remove the eight stud bolts (4) from the ported
section (14). Save the stud bolts for reassembly.
15. Remove the four long bolts (19), lockwashers (20),
four short bolts (21) and lockwashers (20) holding
the secondary section cover (22) and rear center
section (23) to the ported section (14) of the pump.
Carefully remove the front cover from the front
center section housing. The two locating dowel pins
(31) will remain in place on the center section.
16. Remove the wear plate (24) and the plastic seal
retainer (25) with the seal gland (26) from the
secondary section cover (22). Discard the seal
retainer with seal gland. Place the wear plate on a
clean surface.
17. Remove the square cross section o-ring (27) from
the secondary section cover (22). Discard the o-ring.
18. Use marking fluid to identify the intersecting teeth of
the drive gear (28) and the driven gear (29).
Carefully remove the driven gear and then the drive
gear from the lower gear bearing block.
19. Remove the splined adapter shaft (30) from the drive
gear (28).
20. Use a plastic mallet to separate the rear center
section (23) from the ported section (14) of the
pump. The two dowel pins (31) which align the rear
center section (23) and ported section (14) are a
tight fit and will require the use of the plastic mallet to
separate. DO NOT use a screwdriver or other pry
tool to separate these parts as damage will result.
21. Remove the front center section from the ported
section.
22. Remove the wear plate (32) and the plastic seal
retainer (33) with the seal gland (34) from the ported
section (14). Discard the seal retainer with seal
gland. Place the wear plate on a clean surface.
23. Remove the square cross section o-ring (35) from
the ported section (14). Discard the o-ring.
24. Remove the outer shaft seal (36) from the mounting
face of the mounting flange housing (5). Use a
internal snap ring pliers to remove the snap ring (37)
holding the inner shaft seal (38) in the mounting
flange housing. Discard the snap ring, outer seal
and inner shaft seal.
25. Remove the weep hole plug (39) from the side of the
pump mounting flange. Discard the plug.
e. Pump Cleaning
Clean all pump components with a suitable cleaner such
as trichlorethylene. Dry all parts thoroughly with a clean,
lintless cloth.
f. Pump Inspection
1. Check the splines on the drive gears (12 and 28) for
twisted or broken teeth, nicks or excessive wear.
Inspect the gear journals for scratches or
discoloration. Any discoloration of shaft requires
replacement of the gear sets. Replace drive gears
and driven gears as matched sets only.
2. Inspect the splined adapter shaft (30) for twisted or
broken teeth, nicks or excessive wear.
3. Inspect the drive and driven gear teeth for scratches
or excessive wear. Light stoning of the teeth to
remove sharp edges is permissible.
4. Inspect the gear face of both drive gears (12 and 28)
and both driven gears (13 and 29). If the face edge
of the gear teeth are sharp, they will mill into the
wear plates. If wear on the face of the gears has
occurred, the gears need to be replaced.
5. Inspect the bearings in the mounting flange
housing (5) for excessive wear, scoring, flaking or
movement of the bearings.
6. Inspect the bearings in the ported section (14) for
excessive wear, scoring, flaking or movement of the
bearings.
7. Inspect the bearings in the secondary section cover
(22) for excessive wear, scoring, flaking or
movement of the bearings.
8. Inspect the gear pockets inside the front center
section (6) and the rear center section (23). It is
normal for the surface inside the gear housing to
show a clean “wipe” on the inside gear pocket wall
on the intake side. There should not be excessive
wear or deep scratches or gouges.
9. Inspect the bronze side of the wear plates (8, 15, 24
and 32) for erosion, pitting, scratches or scoring.
Replace if damaged.
Note: Refer to the parts manual when ordering kits to
repair or replace sections of this pump. Not all parts of
this pump are serviced separately.
Note: ALWAYS replace seals, o-rings, gaskets, etc.,
with new parts to help ensure proper sealing and
operation. Lubricate seals and o-rings with clean
hydraulic oil.