Lull 944E-42 Service Manual - Manual (Page 431)

8.179 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
b. Main Control Valve Disassembly
1. To disassemble the main control valve (1), remove
the four hex socket head capscrews (2) which hold
the inlet section (3), transfer carriage section (4),
auxiliary hydraulic section (5) to the mono block
section (6).
IMPORTANT: Refer to Section 8.7, “Hydraulic System
Testing,” to properly test and reset any relief valve
pressure settings if necessary.
2. The four socket head capscrews (2) are threaded
into the mono block section (6). Pull the four
capscrews all the way out of the sections.
Inlet Section Disassembly
1. Remove the inlet section (3) from the transfer
carriage section (4). Remove the three small o-rings
(7) and the large o-ring (8) from between the
sections. Discard the o-rings.
2. Remove the main relief valve (9) from the inlet
section (3). Remove and discard all seals.
Note: The internal parts of the relief valves are not
serviceable. Replace the entire relief valve if necessary.
3. Remove the unloader valve (10) from the inlet
section (3). Remove and discard all seals.
Note: The internal parts of the unloader valve are not
serviceable. Replace the entire unloader valve if
necessary.
Transfer Carriage Section Disassembly
1. Remove the transfer carriage section (4) from the
auxiliary hydraulic section (5). Remove the three
small o-rings (11) and the large o-ring (12) from
between the sections. Discard the o-rings.
2. Remove the relief valves (13 & 14) from the transfer
carriage section (4). Remove and discard all seals.
Note: The internal parts of the relief valves are not
serviceable. Replace the entire relief valve if necessary.
3. Remove the hex socket head capscrews (15) holding
the spool end housings (16) to the section. Remove
the housings, o-rings (17), springs (18) and pistons
(19). Discard the o-rings.
Note: The spool in the section is not serviceable
separately. If the spool is scratched or nicked the entire
section must be replaced.
4. Remove the hex plug (20) and o-ring (21) from the
top of the section. Discard the o-ring. The two
plungers (22) of the compensator are not serviced
separately. If these parts require replacement the
entire section has to be replaced.
5. Remove the spring (23) from between the plungers.
Auxiliary Hydraulic Section Disassembly
1. Remove the auxiliary hydraulic section (5) from the
mono block section (6). Remove the three small o-
rings (24) and the large o-ring (25) from between the
sections. Discard the o-rings.
2. Remove the relief valves (26 & 27) from the auxiliary
hydraulic section (5). Remove and discard all seals.
Note: The internal parts of the relief valves are not
serviceable. Replace the entire relief valve if necessary.
3. Remove the hex socket head capscrews (28) holding
the spool end housings (29) to the section. Remove
the housings, o-rings (30), springs (31) and pistons
(32). Discard the o-rings.
Note: The spool in the section is not serviceable
separately. If the spool is scratched or nicked the entire
section must be replaced.
4. Remove the hex plug (33) and o-ring (34) from the
top of the section. Discard the o-ring. The two
plungers (35) of the compensator are not serviced
separately. If these parts require replacement the
entire section has to be replaced.
5. Remove the spring (36) from between the plungers.