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FIGURE 8-2. HOIST VALVE ASSEMBLY
1. Inlet Section (Rear)
2. Spool Section (Work Ports)
3. Spool Section (Tank Ports)
4. Inlet Section (Front)
Installation
1. Attach a suitable lifting device that can handle the
load safely to the hoist valve. Move the hoist
valve into position and secure in place with cap-
screws, nuts and lockwashers. Tighten cap-
screws to standard torque.
Note: Valve should be positioned with separator plate
(8, Figure 8-2) toward front of truck.
2. Using new O-rings at the flange fittings, connect
hydraulic lines. Tighten flange capscrews to
standard torque. Refer to Figure 8-1 for hydraulic
line location.
3. Connect pilot supply lines, tighten fittings se-
curely.
4. Start the engine. Raise body and remove safety
cable. Lower and raise body to check for proper
operation. Observe for leaks.
5. Service hydraulic tank if necessary.
FIGURE 8-3. TIE ROD INSTALLATION
L8-2
5. Nuts and Washers
6. Tie Rods
7. Tube
8. Separator Plate
Hoist Circuit Component Repair
O-Ring Replacement
NOTE: It is not necessary to remove the individual
valve sections to accomplish repair, unless emergency
field repair is required to replace the O-rings between
sections to prevent leakage. Loosening and retighten-
ing of the main valve tie rod nut could cause distortion
resulting in binding or severely sticking plungers, pop-
pet and spools.
To replace the O-rings between the valve sections:
1. Remove the four tie rod nuts and washers (7,
Figure 8-2) from one end of the valve. Slide the
tie rods from the valve and separate the sections.
2. Inspect the machined sealing surfaces for
scratches or nicks. If scratches or nicks are
found, remove by lapping on a smooth flat steel
surface with fine lapping compound.
3. Lubricate the new O-rings lightly with multipur-
pose grease. Replace O-rings between sections.
Stack the sections together making sure O-rings
between the sections are properly positioned.
4. Install the four tie rods with the dished washer
between the nut and housing (Figure 8-3).
5. A torque wrench should be used to tighten the
nuts in the pattern shown in Figure 8-4. The tie
rods should be tightened evenly to 105 ft. lbs.
(142 N.m) torque in the following sequence:
a. Tighten nuts evenly to 15 ft. lbs. (20 N.m)
torque in order 1, 4, 2, 3.
b. Tighten nuts evenly to 32 ft. lbs. (43 N.m)
torque in order 1, 4, 2, 3.
c. Tighten nuts evenly to 105 ft. lbs. (142 N.m)
torque in order 1, 4, 2, 3.
FIGURE 8-4. TIGHTENING SEQUENCE
L08024
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