Operating Instructions
Form No. 102838
PROBLEM CAUSE SOLUTION
Pump builds pressure but cannot
maintain pressure.
Pump will not build full pressure
1. Check to see if there are any
external leaks. If no oil leakage
is visible, the problem is internal.
If using a double-acting cylinder,
remove it from the system to
ensure that the leak is not in the
cylinder.
2. To test for a leaking control
valve lift the pump from the
reservoir but keep the filter in
the oil. Remove the drain line to
see if the oil is leaking from the
valve. If the valve is not leaking,
the internal check valve could
be leaking. Refer to the note
concerning checking for oil leaks
at the beginning of this Trouble-
shooting Guide.
1. Check for external leakage.
2. Check the relief valve setting.
3. Look for internal leakage in
double-acting cylinders.
4. Check for leaks in the flow
control valve.
5. Inspect the pump for internal
leakage. Check high pressure
pump inlet or outlet ball checks.
6. Sheared key(s).
1. Seal leaking pipe fittings with
pipe sealant.
2. Clean, reseat or replace flow
control valve parts. If the internal
check valve(s) are leaking, the
pump must be dismantled and
the seat areas repaired, poppets
replaced, etc.
1. Seal faulty pipe fitting with pipe
sealant.
2. Lift the pump from the reservoir,
but keep the filter immersed in
oil. Note the pressure reading
when the relief valve begins to
open. If functioning normally, it
should start to leak off at relief
valve pressure.
3. Remove the cylinder from the
pump. If the pump builds full
pressure, the cylinder is
defective.
4. Clean and reseat or replace
parts.
5. Same procedure as above, but
look for leads around the entire
inner mechanism. If there are
no visible leaks, the high
pressure pump subassembly
may be leaking. Remove all
parts. Check the valve head
assembly body for any damage
to the seat area. Clean and
reseat if necessary. Inspect for
damage and replace parts if
necessary, then reassemble.
6. Replace.
Sheet No.
3 of 3
Rev. 7
Date: 25 May 2012
