Hydraulic System

Symptom Problem Solution

All hydraulic system fails to function.

Bad fuse.

Replace fuse.

Low oil supply.

Fill system with proper oil to center of hydraulic reservoir sight tube.

Clogged suction line.

Clean line.

Damaged pump drive coupling.

Replace coupling.

Pump faulty.

Replace pump.

Oil escapes at reservoir breather.

Reservoir over-filled.

Reduce oil to center of sight tube.

Excessive speed on rough terrain.

Reduce speed.

Booms level or fold too fast.

Incorrect orifice, or none in work port.

Use correct orifices, properly installed.

Lift arms drop too fast.

Incorrect orifice, or none in work port.

Use correct orifices, properly installed.

Some functions work erratically or not at all.

Loose or disconnected wires at switch or solenoid.

Check and repair connections.

Failed solenoid coil.

Replace coil.

Low oil.

Fill tank to proper level.

Erratic steering.

Hydraulic oil overheated.

Fill tank to proper level.

Clean oil cooler and screens.

Pump faulty.

Replace pump.

All hydraulic functions but one do not work or are slow.

Check valve in load sense line of function that works properly is stuck open.

Clean or replace check valve or see your John Deere Dealer.

NXH8,M68440,L3 -19-10JUL98-1/2


Symptom Problem Solution

One hydraulic function fails to work properly.

Bad fuse.

Replace.

Bad switch.

Repair or replace.

Solenoid for hydraulic function faulty.

Repair or replace.

Check valve in load sense line in hydraulic valve sticks shut.

Clean or replace check valve.

Hydraulic spool not shifting properly.

Clean or replace or see your John Deere dealer.

NXH8,M68440,L3 -19-10JUL98-2/2