WARNING
The main control valve weighs approximately
30.5 kg (67 lb). Use a lifting device capable of lift-
ing the main control valve to avoid the possibility
of injury to personnel.
10.
Support the main control valve with a lifting
device. Remove three mounting capscrews,
washers, and inserts from the main control
valve. See Figure 5.
NOTE:
To aid in installation, tag all connectors
prior to disconnecting from the solenoids.
11.
Raise the main control valve approximately
25.4 cm (10 in.) to gain access to the lower tilt
and auxiliary function Proportional Pressure
Reducing Valve (PPRV) solenoids. Disconnect
the cowl harness from the lower tilt and auxili-
ary function (PPRV) solenoids.
1. COWL
2. INSERT
3. WASHER
4. MOUNTING CAPSCREW
5. MAIN CONTROL VALVE
6. FRAME
Figure 5. Main Control Valve Removal
12.
Remove the main control valve from cowl.
MAIN CONTROL VALVE SECTIONS
General
CAUTION
While working on an electro-hydraulic main con-
trol valve section, place a cover over the remain-
ing sections of the control valve to prevent the
possibility of contaminants getting into the con-
trol valve openings which could cause damage to
the control valve.
CAUTION
If O-rings are to be replaced between two sections
that have a hydraulic oil leak, replace all O-rings
between all sections. This eliminates the possibil-
ity of a subsequent oil leak or possible damage to
another O-ring.
Disassemble the electro-hydraulic main control
valve only as necessary for repairs. Most repairs to
the control valve will be for the replacement of O-
rings to stop leaks between sections.
Outlet Control Valve Section
Remove
1.
Remove four nuts from the control valve tie
rods. See Figure 6.
2.
Remove the outlet control valve section from
the four tie rods and discard 10 O-rings (item
13 in Figure 7) from the auxiliary control valve
section.
Disassemble
1.
If the secondary relief valve has been leaking,
remove it from the outlet control valve section.
See Step 2 through Step 7. See Figure 6.
2.
Remove the plug from the adjusting nut. Re-
move and discard the O-ring from the plug. Re-
move and discard the backup rings and O-ring
from the adjusting nut. See Figure 6.
2000 SRM 1899
Main Control Valve Repair
5