TM 9-3418-201-14&P
If the pump is new or has been overhauled, be certain it
loading of' the drive shaft.
is properly installed. Check the direction of shaft rotation
Pump life will be shortened by operation beyond
and alignment of the shaft with the drive motor. Since it
maximum pressure and speed ratings. Since these units
is difficult to achieve perfect shaft alignment, a flexible
are positive displacement, a relief valve must be used to
coupling must be used.
limit maximum system pressure to recommended limits.
Exercise care with pumps driven by belts, chain drives,
spur gears, etc. to prevent excessive side
TROUBLESHOOTING CHART
TROUBLE
PROBABLE CAUSE
REMEDY
PUMP NOT DELIVERING FLUID
Pump driven in wrong direction of
Must be reversed immediately to
rotation.
prevent seizure. Check direction
of drive rotation against proper
pump rotation as indicated by arrow
on body.
Pump drive shaft broken or shaft
Remove pump from accessory
key sheared (direct drive).
mounting pad and determine dam-
age to pump cartridge. Replace
needed parts.
Fluid intake pipe in reservoir
Drain complete system. Add new
blocked or oil viscosity too heavy
fluid of proper viscosity. Filter
to pick up prime. Viscosity should
the new fluid as recommended.
not exceed 4000 S. S.U.
Checkall filters for dirt and sludge.
Air leaks at intake.
Check intake connection for air
leak. Tighten securely.
Pump not priming.
Loosen connection in outlet line.
Bleed-off air until fluid flows.
Oil level too low.
The fluid level must be above in-
take opening in intake pipe. Check
minimum drive speed which may be
too slow to prime the pumps.
Vane or vanes stuck in rotor
Inspect rotor slots for wedged chips
slots.
or foreign particles and replace all
damaged parts. F 1 u s h complete
system thoroughly by recommended
processes and fill system with new,
clean hydraulic fluid.
PUMP MAKING NOISE
Partially clogged intake strainer
Pump must receive intake fluid freely
or restricted intake pipe.
Drain system, clean intake pipe,
and clean or replace strainer. Add
new fluid and strain by recommended
procedures.
Defective bearing.
Disassemble pump and replace
bearing.
Air leak at pump intake piping
Test by pouring oil on joints and
joints or pump shaft seal.
around drive shaft. Listen for
change in operation. Tighten joints
affected. Check pump shaft oil seal
for leakage and replace if necessary,
in accordance with instructions out-
lined in this manual. Check' shaft
for scoring at seal contact area and
replace shaft if grooving is evident.
Coupling misalignment.
Check shaft bearing and seal for
possible damage. Replace if
necessary. Re-align shafts.
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