Figure 10 - 4 Way Solenoid Operated Hydraulic Valve - Exploded View
(11) Manual Test Operation of Solenoid Valve - If a properly tested substitute coil and electrical wiring system
fails to operate a valve, a means is provided for manual shifting of the spool which may be temporarily jammed. (See
Figures 9 & 11).
Use a ¼" diam. X 1 ½" long steel pin or similar tool which will enter the bore of the valve tube. With the paver engine at
full throttle, and all hydraulic system toggle switches in the OFF of center position, depress the pin in the bore of the
valve tube so that it contacts and moves the plunger, pin, and spool toward the opposite end of the valve. The first 1/8"
movement will require nearly 25 pounds of force. As long as the valve is held manually depressed the cylinder operated
by the valve receives hydraulic fluid. If the spool has been jammed by dirt particles the flushing action of flow through
the valve may permanently correct the problem and normal operation can be resumed. Do not use unreasonable
pressure for manual shifting! If the spool cannot be manually shifted or fails to return by spring action to the OFF
position, the valve should be completely dismantled, inspected, cleaned, and test operated. (See following paragraph) If
manual shifting succeeds in operating the system, try electrical operation again to see whether the coil's magnetic force
is strong enough to consistently move and hold the plunger.
Figure 11 - Manual Operation of Solenoid Valve