Operation and maintenance manual

Section 220-0000
SM 1390 Rev 2 2-02
5
Steering System - Steering System Schematic
AMPLIFIER VALVE DIAGNOSIS
TABLE62
7
CONDITION REASON REMEDY
Too few steering wheel turns from
stop to stop
Dirty, leaky or missing check
valve
Clean or renew check valve
Steering over-reacting Amplifier spool stuck in open position Disassemble and check amplifier
spool movement
Too many steering wheel turns from
stop to stop
Steering too slow
Amplifier spool stuck in closed
position
Disassemble and check amplifier
spool movement
Prolonged hard point when beginning
to turn the steering wheel
Amplification is delayed and sets in
suddenly
Dirty orifice in directional spool Clean or replace orifice
Dirty orifice in amplifier spool Clean or replace orifice
Dirty orifice in valve housing Clean or replace orifice
Dirty orifice in 'LS' port Clean or replace orifice
Blocked up throttle check valve in 'PP'
port
Clean or replace throttle check valve
Steering wheel can be turned rapidly Setting of shock & anti-cavitation
valve set too low
Untighten the counter nut and adjus
t
the valve setting screw with an allen
key. Tighten the counter nut to
secure.
Leaking or hanging shock &
anti-cavitation valve
Disassemble shock & anti-cavitation
valve and renew, if necessary
No end stop feeling Missing end stop in directional
spool
Mount end stop
Steering has insufficient force to turn
the wheels at standstill
System relief valve adjusted too low Remove plug and adjust pressure
setting with an allen key
Steering unit spool and sleeve
installed in wrong manner to each
other. No 'LS' signal can be built up.
Disassemble steering unit and turn
the spool and sleeve to the right
position
Steering unit spool and sleeve worn Change steering unit
No function at all Oil flows direct from pump to tank in
the steering unit
Manual steering ball is missing
Short hard point when beginning to
turn the steering wheel
Air in the 'LS' and 'PP' lines Bleed 'LS' and 'PP' lines
Clogged orifice in 'LS' port and/or
clogged check valve in 'PP' port
Clean the orifice and/or check valve