New Holland WorkMaster 50 Service Manual page 393

Hydraulic systems - Troubleshooting
Problem
Lift arms lift jerky
Lift arms do not lift
Lift arms do not lower
Lift arms do not lower full
travel
Low lift capacity
Lift arms cycle up and
down with load applied
with engine running
Lift arms leak down when
engine is not running
When lift arms are at
maximum lift height, with
the engine running, the lift
arms cycle up and down
Hydraulic systems - Hydraulic systems
Possible Cause
Hydraulic oil level low
Suction Filter is clogged
Pump has an air suction leak
Inner control valve spool not shifting to
open position
Regulator valve not shifting
Discharge valve blocked
Lowering response valve closed
Incorrect adjustment of the position control
lever
Control valve sensitivity adjustment not ad-
justed correctly
Damaged control valve outer diameter
O-rings
Relief valve not adjusted correctly
Worn lift cylinder piston seal
Lift cylinder piston seal damaged
Discharge valve not adjusted correctly
Lift check valve not seating properly
Safety valve not seating properly
Lift cylinder piston seal damaged
Discharge valve not adjusted correctly
Lift check valve not seating properly
Safety valve not seating properly
Position control lever maximum height po-
sition not adjusted correctly
47866583_ 02/12/2015
35.1 [35.000] / 8
Correction
Add hydraulic oil to correct level
Replace oil filter
Check all inlet pipe connections
Remove control valve and clean spool
Remove and clean regulator valve
Remove discharge valve and clean
Open lowering response valve by turning
counterclockwise
Adjust position control lever
Adjust control valve sensitivity
Replace O-rings as necessary
Adjust relief valve to specification
Replace damaged seal
Replace piston seal
Adjust sensitivity of control valve
Inspect lift check valve for contamination
Inspect safety valve for contamination
Replace piston seal
Adjust sensitivity of control valve
Inspect lift check valve for contamination
Inspect safety valve for contamination
Adjust position control lever maximum po-
sition setting