4718 lost hydraulic lifting power (front)

[scherpbier]

Have a 4718 which can not lift enough. 350 kg is allready to heavy to pick up. front arm is functioning normally. Up and down goes smoothly and when i use the gasthrottle he lifts faster and generates a little bit more power. The handle under the seat is pointing to the right 1000 v/min.

All the air is out of the hydraulic lifting cilinders and because the oil was grey of air i changed the oil today. Cleaned the magnetic filter under the seat and the one under the metal plate under the traktor. Still know improvment.

Can somebody help me with this problem?
What can be the problem?

Martijn from Sweden

 

[Renze]

Probably one of the rubber O rings between the pipe from the oil pump to the 3pt lift valve blew. There is one at the pump (accessible by dropping the round plate, with oil pump, from under the differential housing) and there is one between the lift cover and the rear axle housing, on the top.

 

[k4]

Hi All,

This post is 10 years old but it's exactly the same issue I am having with my 4718. With the help of a friend I have replaced the pump/plate unit and the head units completely to try to get the lift arms back working again but no luck. They were lifting really slowly but could only lift their own weight the last whilr but now there is no movement at all.

All o-rings have been replaced, pump filter cleaned and a new lift ram on the head unit too. When I engage the hydraulics to lift a tipping trailer ram there is no issue but the lift arms just won't budge a bit. There is oil been pumped to the head unit as the tipping hydraulic works perfectly and it is reaching the magnet on top of the unit but I cannot get the lift arms to engage at all no matter what way I have the PTO and hi-low Gears handles engaged.

Looking for some guidance here folks please on next steps?

 

[ixer0]

Hi,

I sounds like you have a valve stuck or popped out. It will be the diff valve which is in the control unit under the top cover. It's a valve that switches from link arms to spool valve. Remove the distributor from the top cover. The valve is one which is held in with a C clip either side of the distributor.

Mike