Rev. 9/25/2017
HDC-450, MANUAL
Copyright 2017 Vestil Manufacturing Corp. Page 13 of 26
Unusual noise or binding
(B) Monthly Inspections:
Determine the oil level. Oil should be 1" to 1-1/2" below the top of the reservoir/tank with the pivot arm fully
lowered. Add oil, if necessary.
Check for oil leaks. Resolve the issue as described in “Troubleshooting” section.
Check the hydraulic system for worn or damaged hoses. Replace damaged hoses as necessary.
Cycle the deck and listen for unusual noise. See "Troubleshooting".
(C) Yearly:
Change the oil at least once a year or sooner if it darkens, is gritty, or appears milky. Milky appearance indicates the
presence of water. Replace the oil with AW-32 hydraulic fluid or its equivalent.
Troubleshooting (Foot Pump):
Issue Explanation Remedy
1. Pivot arm does not rise
despite pumping pedal
a. Too much weight applied to the
saddle (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 carrier
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 arm
does not rise or rises 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. Pivot arm rises only when
unloaded or pedal pumped
rapidly
OR
I can pump the pedal but
the arm does 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 “Purging
air from the pump,” p. 10).
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. Arm rises during the down
stroke of the pedal, but
lowers 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. Pivot arm rises and
maintains elevation, but
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. Pivot arm rises 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
pivot arm rises in jerks
n. Oil level is low
o. Air present in pump and/or cylinders
n. Add oil until level is within 1in. of top of
reservoir.
o. Purge air by following “Purging air from
the pump” and “Purging air from the
cylinder” on p. 10.
8. Pivot arm lowers very
slowly
p. Flow control valve obstructed
p. Remove valve and inspect for debris or
non-operating spool
9. Arm lowers too rapidly
q. Flow control valve obstructed or not
moving freely
q. Remove valve and inspect for debris or
non-operating spool
10. Pivot arm rises part way
and then stops
r. Air trapped in small pump chamber
r. Perform “Purging air from the pump” on p.
10.
