New Holland Workmaster 50, Service Manual

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Hydraulic systems - Main lift system
Main lift system - Troubleshooting
Problem Possible Cause Correction
The Rockshaft lifts jerkily Insufficient oil level in the tank Top up the level
Pump inlet filter clogged Clean or replace the filter
Infiltration of air into the pump inlet pipe Check the inlet pipe and any coupling and
gasket
Rockshaft does not
operate Differential valve blocked or dirty Remove the control valve and unblock the
regulator piston
The rock shaft starts to
lift, but it stops as soon as
it feels the load, without
the functioning of the
over-pressure valve Tension rod measurement (L) is not cor-
rect (Refer to Main lift system - Adjust
(35.100) )
Adjust the draft control lever (Refer to Main
lift system - Adjust (35.100) )
The rock shaft does not
descend over its entire
travel Faulty adjustment of the position control
lever
(1)
Adjust position control lever (Refer to Main
lift system - Adjust (35.100) )
The rock shaft does not
descend Discharge valve blocked Remove control valve and unblock or clean
discharge valve
Lever RD closed Turn lever RD in anti-clockwise
Lifting capacity does not
match that prescribed Deterioration of the control valve seal rings Remove control valve and replace the ex-
ternal seal rings
Relief and safety valves out or calibration Control calibration of the valves
Poor pump efficiency Replace the pump
Excessive loss of oil from control valve Overhaul the control valve
The rock shaft supports
loads with difficulty Piston gasket worn Replace the gasket
When the motor is off Oil leakage from safety valve Remove control valve and adjust valve
Oil leakage from check valve Remove the control valve and adjust valve
With the arms raised at
backstop and with the
engine on, we have
verified a rhythmic
oscillation, with the
engine off the load does
not lower Incorrectly adjusted of position control lever
which, at maximum raised height, causes
the internal automatic backstop to function Adjust the position control lever (Refer to
Main lift system - Adjust (35.100) )
The draft control does not
function, the rock shaft
raises and lowers only
with the position lever Draft control lever is adjusted badly Adjust the draft control lever ( Main lift sys-
tem - Adjust (35.100) ).
The position control does
not function, the rock
shaft raises and lowers
only with the draft lever Position control lever is adjusted badly Adjust the position control lever (Refer to
Main lift system - Adjust (35.100) )
Rockshaft does not lift
and the relief valve acts
with the possibility to
damage the pump Pre selector i s fully closed Unscrew fully the pre-selector (P) (Refer to
Main lift system - Adjust (35.100) ).
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