Yanmar ViO12-2A, Service Manual

Page: 391 / 409

10. TROUBLESHOOTING
10-2-16
Cannot travel straight
Hydraulic
power source
Do other implements work
normally?
Lift machine body and
check R and L revolutions
Check hydraulic
pump
Crawler tension,
clogging
Control valve
Swivel joint Oil leak
Internal
leakage
Brake valve
(or counter balance valve)
Dust in
check valve
R and L relief valves
pressure
Dust in
control valve
Controls
Link operation Wear of link joint
Wear of relief
valve seat surface
Internal
leakage
Malfunction of
2-speed spool
Hydraulic
motor
Oil leak
Replace
2-spool valve
Replace
Replace
Improper adjustment of
lever stopper bolt
Readjust
Replace motor
Replace seal Replace seal
Repair or replace
Replace hydraulic
pump
Replace seal or
whole assembly
Clean
Clean
Wear of check
valve seat surface
Sticking of
plunger
Repair or replace Repair or replace
Check the pressure and
adjust it. Refer to section
5-4 Pressure Adjustment"
Before making checks, remove dirt from
undercarriage, and adjust crawler tension.