Hydraulic System - Husqvarna PT26D Workshop Manual

Hydraulic System

Hydraulic diagram is available as Appendix "Hydraulic diagram" on page 161.
In many cases the hydraulic system is controlled by the electrical system. In other cases the system is con-
trolled mechanically. First make sure that the components in the system receive the correct and control
commands. See "Function table solenoid valve" on page 135.
• Does the electrical system work correctly?
• Is the linkage or control undamaged and set correctly?
For trouble shooting components refer to the Sauer-Danfoss test and service instructions.
See "System components Manuals" on page 48. Most connections on the machine permit you to connect
test nipples to take pressure measurements.
Trouble shooting without pressure
measurement
Weight transfer
Start the machine and move the joystick forwards. The cutting unit is lowered towards the surface and rests
on the swivel castors. A small motion is shown at the cutting unit attachment when the switch is flicked.
Feed pressure
The drive system's hydraulic pump is equipped with a test socket for the feed pressure on the right-hand
side of the pump. The feed pressure should be 1.8 MPa (18 bar).
If you do not have access to a pressure
gauge you can still get an indication of the
feed pressure:
1. Remove the cutting unit.
2. Set weight transfer in position 0.
3. Lower the lifting arms.
4. Set weight transfer in position 1.
5. With the lift lever in the floating position the lifting arms should go up.
A low feed pressure can also be due to internal leakage in the control unit or lift cylinder.
Wheel motors
WARNING!
Do not block the wheels with your
hands or feet. Use tools, e.g. small
bars.
Lift up both axles. Hold one axle at a time. Drive at a low speed and with the differential lock activated.
Block both wheels with a suitable tool. Ifthis is possible the fault lies in the lifted axle or flow distributor. See
Danfoss manual to rectify.
Control unit
Check if there is "springing" in the steering wheel when the engine is off. If there is no springing the steer-
ing unit is defective.
Jerky steering indicates defective steering unit.
Check that the steering wheel moves equally easily in both directions and that it does not steer in one
direction by itself.
In case of defective steering unit: Replace steering unit, contact Sauer Danfoss service organisation or
take action as set out in Sauer Danfoss manual, see page 48.
TROUBLE SHOOTING
131
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