TROUBLESHOOTING /SYSTEM PERFORMANCE

Ｄ-7. Bucket tilts forward with control valve in "Hold (Neutral)" state (front wheels cannot be raised off ground)

（１）Check the tilt cylinder for internal leakage.

Check the tilt cylinder for internal leakage.

1. Lower the lift arm to the lowest position and tilt back the b ucket.

2. Disconnect the hose ① from the piston rod end (cylinder head) and close the disconnected end of the hose ① with the plug ② to prevent oil from spouting from the hose.

3. Start the engine and place the control lever in the "Tilt-bac k" position to apply oil pressure to the cylinder bottom end.

4. If oil flows out from the cylinder port ③, the cause can be d etermined to be damaged piston seals in the cylinder.

Repair the tilt cylinder.

（２）Poor oil-tightness of overload relief valve

Check the overload relief valve for oil-tightness.

1. Check that the front wheels can be raised and held off the gr ound by the tilt cylinder.

2. If foreign matter is jammed into the overload relief valve or the valve is in poor contact with its seat, pressure fluid in the piston rod end flows dir ectly to the tank circuit via the overload relief valve, so the tilt cylinder rod cannot be hel d in an extended position (front wheels gradually lower).

3. As the overload relief valves in the piston rod end and cylin der bottom end are the same, functionality of both the valves can be checked by interchang ing them.

4. If oil-tightness of the cylinder bottom end overload relief v alve is defective, the bucket spontaneously tilts forward . If oil-tightness of the piston rod end overload relief valve is defective, the front wheels cannot be raised and held off the ground

Oil-tightness of the overload relief valves is defective.

Clean or replace the overload relief valve(s).

Oil-tightness of the overload relief valves is normal.

Troubleshooting