42
Pub. 1147 - Rev. 7 SEPTEMBER 2004
Mechanical Dock Leveler Hydraulic Conversion
Problem
Probable Cause
Remedy
6. Platform does not lower.
a. Hydraulic fluid level is low.
a.Check oil level in tank.
Refill if there is less than 3-1/2" of oil in
the tank when the unit is held open
with the SAFE-T-STRUT™. Do not
exceed maximum oil level indicated by
the “Oil Level” decal on the reservoir
(approximately 3-1/2" depth).
b. Velocity fuse has locked up due to air
b. Attempt to raise unit to unlock the
trapped in the system.
velocity fuse. Cycle unit (5 to 10 times)
until velocity fuse no longer locks up.
c. Velocity fuse has locked up due to a
c. Loosen the shuttle valve adjustment
misadjusted shuttle valve.
screw and cycle unit (5 to 10 times)
until velocity fuse no longer locks up.
d. Velocity fuse has locked up because of
d. Remove weight and cycle unit (5 to 10
weight on the platform.
times) until velocity fuse no longer
locks up.
e. Debris is lodged on or around the
e. Check for and remove any lodged
leveler.
materials on or around the leveler.
f. The power unit did not shut off, causing
f. Verify that the ARTD actuator is
the platform to remain in the fully raised
functioning properly
position.
Verify that ARTD and restrictor limit
switches are functional.
g. Debris in the hydraulic system.
g. Consult factory.
7. Platform raises very slowly.
a. Weight on top of platform.
a. Remove weight from platform.
b. Hydraulic fluid level is low.
b. Check oil level in tank.
Refill if there is less than 3-1/2" of oil in
the tank when the unit is held open
with the SAFE-T-STRUT™. Do not
exceed maximum oil level indicated
the “Oil Level” decal on the reservoir
(approximately 3-1/2" depth).
c. System leak.
c. Check hoses, fittings, valves and
power unit for leaks.
d. Shuttle valve is not adjusted properly.
d. Readjust shuttle valve.
e. Adjustable system relief valve pressure
e. Readjust until the relief pressure is
is set too low.
1200 psi.
f. Low voltage.
f. Verify ±10% nominal voltage while unit
is running.
g. Debris in the hydraulic system.
g. Consult factory.
h. Power unit/pump/motor failure.
h. Replace power unit.
i. Platform cylinder failure.
i. Replace platform cylinder.
8. Lip extends slightly when the
a. Adjustable sequence valve spring
a. Increase the sequence valve spring
platform starts to raise.
pressure is set too low.
pressure.
9.
Lip does not remain extended while
a. Valve failure on power unit endhead.
a. Inspect, test and replace the pilot to
the platform is lowering
close check valve if necessary.
10. Lip does not store or store properly
a. The lip stop bolt is not adjusted
a. Verify that the lip stop bolt is properly
in lip supports.
properly.
adjusted.
b. Debris.
b. Remove debris from the lip supports
and hinge spools.
c. Lip supports are damaged.
c. Inspect, repair or replace the lip
supports as needed.
d. ARTD actuator failure.
d. Verify that the ARTD actuator is
functioning properly.
