
7 - TROUBLESHOOTING
Problem
Possible Cause
Correction
Worn out control valve.
Replace the valve.
Check that the check ball in the anti-cavita-
tion is seated properly.
Clean the anti-cavitation valve properly. Be
sure that it moves freely and is correctly
placed or replace it.
Dampening in swing
cylinders malfunctioning
Loose hydraulic hoses, leaking moving
parts or hoses.
Tighten hoses, replace damaged O-rings if
leaking. Replace damaged hoses.
Limitations to movable parts or hoses.
Replace damaged hoses and movable
parts. Check stripped hoses.
Piston in lifting cylinders leaks.
Contact your dealer.
Piston unit damaged (does not seal).
Contact your dealer.
Worn out or damaged piston seal. External
leakage.
Contact your dealer.
Lifting cylinder piston rods bent.
Contact your dealer.
Spool does not have full stroke.
The spool motion should be 5/16” in one
direction or 5/8” total.
Pressure relief valve working irregularly or
set too low.
Contact your dealer.
Worn out control valve.
Replace the valve.
Check that the check ball in the anti-cavita-
tion valve is seated properly.
Clean the anti-cavitation valve properly. Be
sure that it moves freely and is correctly
placed or replace it.
The swing radius is
limited
Piston in lifting cylinders leaks.
Contact your dealer.
Piston unit damaged (does not seal).
Contact your dealer.
Lifting cylinder piston rods bent.
Contact your dealer.
The swinging boom is stuck.
Remove disruptions.
The cylinder restrictor is blocked.
Remove and clean the restrictors.
Hydraulic hoses incorrectly connected.
Check and connect hoses correctly.
The machine is
functioning slowly
Low hydraulic oil level.
Check and top up with hydraulic oil.
Low hydraulic oil level. Cold hydraulic oil. Check and top up with hydraulic oil. Allow
the hydraulic oil warm up to working tem-
perature.
Low system pressure.
Contact your dealer.
Excessive back pressure.
Restriction between the “in” and “out” port
and the reservior.
Pressure relief valve working irregularly or
set too low.
Contact your dealer.
The cylinder restrictor is blocked.
Remove and clean the restrictors.
Jerking motions on the
cylinder and running
noisily.
Low hydraulic oil level.
Check and top up with hydraulic oil.
Air in the system.
Air out the system by operating the cylin-
ders repeatedly. Check that the oil is not
foaming or any other type of leaking has oc-
curred. Fill with oil.
Low hydraulic oil level. Cold hydraulic oil. Check and top up with hydraulic oil. Allow
the hydraulic oil warm up to working tem-
perature.
Low system pressure from pump.
Check the power outlet. Connect the pump
to the power outlet.
The cylinder restrictor is blocked.
Remove and clean the restrictors.
Lift, dipperstick or bucket
tips when lifted
Piston in lifting cylinders leaks.
Contact your dealer.
Piston unit damaged (does not seal).
Contact your dealer.
Worn out control valve.
Replace the valve.
Check that the safety valve in the control
valve is not stuck.
Clean the safety valve thoroughly and
make sure it can move freely. If there is a
problem, replace the valve.
7-2
Summary of Contents for 905GBL
Page 4: ......
Page 34: ...3 CONTROLS AND INSTRUMENTS 3 4 ...
Page 42: ...4 TRANSPORT OPERATIONS 4 8 ...
Page 58: ...5 WORKING OPERATIONS 5 16 ...
Page 70: ...6 MAINTENANCE 6 12 ...
Page 74: ...7 TROUBLESHOOTING 7 4 ...
Page 83: ......