Unloader Head
64
Disassembly
1. Remove cylinder head from body same as
standard head.
2. Remove solenoid valve.
3. Remove check valve.
4. Remove unloader valve.
NOTE: It may be necessary to tap valves slightly
to loosen from head.
Repair
1. Inspect solenoid valve for physical change.
2. Measure resistance of coil or check for
amperage.
3. With valve de-energized, flow will be from
Port A to C and none from B to C.
4. With valve energized, flow will be from B to
C and A to C closed.
NOTE: The valve is non-repairable.
5. Inspect check valve for wear on sides. If wear
is present, valve must be replaced.
6. Inspect unloader valve.
NOTE: It may be necessary to disassemble
valve assembly to check spring and clean
internal portion of piston. To disassemble
piston from cover, depress piston and remove
roll pin. Compress spring and remove
retaining ring.
a. Inspect piston sides for wear.
b. Remove ring, insert into bore, check end
gap clearance. Gap must not exceed 0.016
in. (0.406 mm).
c. Inspect spring ends, cover and unloader
piston and sleeve for wear.
To reassemble, reverse the disassembly
procedure.
1.
Port A
2.
Port C
3.
Port B
Figure 104: Solenoid Valve Ports
1
2
3
1
2
3
AGA777
