New Holland WorkMaster 50 Service Manual page 483

Steering control - Troubleshooting
Problem
Steering wheel is heavy
to turn
Hard point when starting
to turn the steering wheel
Regular adjustments of
the steering wheel are
necessary ("snake-like
driving")
Neutral position of
steering wheel cannot
be obtained, i.e. there is a
tendency of "Motoring"
"Motoring" effect. The
steering wheel can turn
on its own
Backlash
"Kick-back" in steering
wheel from system. Kicks
from wheels
Heavy kick-back in
steering wheel in both
directions
Turning the steering
wheel activates the
steered wheels opposite
Steering - Steering control
Possible Cause
No or insufficient oil pressure
a) Pump does not run
b) Pump defective
c) Pump runs in the wrong
the direction
d) Pump is worn out
e) Pump is under dimensioned
Pressure relief valve is stuck in open posi-
tion or setting pressure is too low
Priority valve is stuck in open position
Too much friction in the mechanical parts of
the vehicle
Emergency steering balls missing
Combination: Downstream system + steer-
ing unit with suction valve and differential
cylinder are inexpedient
Spring force in priority valve too weak
Air in LS and /or PP pipes
Clogged orifices in LS or PP side priority
valve
Oil is too thick (cold)
Leaf spring without spring force or broken Replace leaf springs
Spring in double shock valve broken
Gear wheel set worn
Cylinder seized or piston seals worn
Steering Column and steering unit out of
line
Too little or no play between steering col-
umn and steering unit input shaft
Pinching between inner and outer spools
Leaf springs are stuck or broken and have
therefore reduced spring force
Inner and outer spools pinch, possible due
to dirt
Return pressure in connection with the
reaction between differential cylinder and
steering unit too high
Cardan shaft fork worn or broken
Leaf springs without spring force or broken Replace leaf springs
Worn splines on the steering column
Fault in the system
Wrong setting of cardan shaft and gear
wheel set
Hydraulic hoses for the steering cylinders
have been switched around
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Correction
Start up pump (loose V-belt)
Repair or replace pump
Correct direction of rotation of pump or re-
place pump
Replace pump
Install a larger pump (examine pressure
need and flow)
Repair or clean pressure relief valve. Ad-
just the valve to the correct pressure
Repair or clean the priority valve
Lubricate bearings and joints of steering
gear or repair if necessary. Check steer-
ing column installation
Install new balls
Change cylinder type (through going piston
rod). If necessary use two differential cylin-
ders
Replace spring by a stronger one ( 4 bar
(58 psi) , 7 bar (102 psi) and 10 bar
(145 psi))
Bleed LS and PP pipes
Clean orifices in spool and in connecting
plugs for LS and PP
Let motor run until oil is warm
Replace shock valve
Replace gear wheel set
Replace defective parts
Align the steering column with steering unit
Adjust the play and, if necessary, shorten
the splines journal.
Contact your authorised NEW HOLLAND
Replace leaf springs
Clean steering unit or contact your NEW
HOLLAND dealer
Reduce return pressure, change cylinder
type or use a non-reaction control unit
Replace cardan shaft
Replace steering column
Contact your authorised NEW HOLLAND
Correct setting as shown in service manual
Reverse the hoses