Rev. 7/14/2016
PMPS, MANUAL
Copyright 2016 Vestil Manufacturing Corp.
Page 16 of 22
Troubleshooting: Manual Auto-shifter Foot Pump
Issue Explanation Remedy
1. Forks do not rise despite
pumping pedal
a. Too much weight on the forks (load
exceeds capacity).
b. Too little oil in hydraulic system
c. Pinched hydraulic hose
d. Relief valve pressure setting too low
a. Remove enough of load that
weight of load is within capacity of
lifter
b. Add oil until level is within one
inch of top of reservoir
c. Correct as appropriate
d. Increase pressure setting as
necessary, but NEVER more than
3,000psi
2. A lot of force is required to
pump the pedal and the
forks do not rise or rise very
slowly
e. Debris under pressure relief valve
f. Debris under inlet check valve
e. Remove, disassemble, clean
(with mineral spirits or kerosene),
reassemble and reinstall pressure
relief valve assemblies.
f. Remove, disassemble, clean
(with mineral spirits or kerosene),
reassemble and reinstall check
valve assemblies.
3. Forks rise only when
unloaded or pedal pumped
rapidly; I can pump the
pedal but the forks do not
move.
g. Pump is air locked
h. Debris on seat of inlet check valve
i. Pressure setting of relief valve
needs adjustment
j. Debris on seat of relief valve
g. Remove air from the pump (see
“Pump purging procedure,” p. 14)
h. Remove inlet check valve and
clean debris from valve seat (the
bottom of the cavity in pump body
that valve fits into)
i. Increase pressure setting as
necessary, but NEVER more than
3,000psi.
j. Remove relief valve and clean
debris from valve seat in pump
body.
4. Forks rise during the down
stroke of the pedal, but
lower during the upstroke.
k. Outlet check valve stuck in open
position
k. Remove, disassemble, clean (with
mineral spirits or kerosene),
reassemble and reinstall outlet
check valve assemblies.
5. Forks rise and maintain
elevation, but I have to
pump the pedal a million
times
l. Autoshifter valve stuck in
closed/deactivated position (piston
out).
l. Remove port plug from port
marked “UL” (on pump body);
then remove piston. Inspect piston
and springs
6. Forks rise very slowly
m. Autoshifter valve stuck in open/
activated position (piston in)
m. Remove port plug from port
marked “UL” (on pump body);
then remove piston. Inspect piston
and springs
7. Pump pedal feels spongy or
forks rise in jerks
n. Debris interfering with carriage
rollers
o. Oil level is low
p. Air present in pump and/or cylinders
n. Clean the inside of the mast and
surfaces of rollers as necessary
o. Add oil until level is within 1in. of
top of reservoir.
p. Purge air by following “Pump
purging procedure” and “Cylinder
purging procedure” on p. 14.
8. Forks lower very slowly
q. Flow control valve obstructed
q. Remove valve and inspect for
debris or non-operating spool
9. Forks lower too rapidly
r. Flow control valve obstructed or not
moving freely
r. Remove valve and inspect for
debris or non-operating spool
10. Forks rise part way and
then stop
s. Air trapped in small pump chamber s. Perform “Pump purging
procedure” on p. 14.
