The Fordson Tractor Pages Forum

The lift on my Super Dexta will not work when I first start the tractor if it has been setting for a few days. After around four or five minutes the lift will begin to work fine and it will work properly for the rest of the day. But when it does not work, it will not move at all. The oil in it is 15-40 Shell Rotella, the temperature is in the mid 60's F. Any ideas?
Thanks,
Terry

Life hydraulics ?

Jos, yes, I have a two stage clutch if that is what you mean. But the pump should pump all the time the motor is running, shouldn't it? The live pto is only for the power take off I believe. Or am I missing something?
Thanks,
Terry

Not an exhaustive list of possible problems......but a place to start.

You didn't say if problem occurs with with selector in position control and draft control. If only in one, problem is possibly in the linkage. If problem exists in either position, linkage is probably ok since it works once warmed up.

easier things to check:
Pressure relief valve in the pump may be leaking or sticking and allowing system to bleed down....
Inlet filter may be plugged up.
The return filter/back pressure valve may be 'sticky' or leaking down.

This one is bit harder to fix....( it's also one the problems I had with mine) .....the unloading valve, in the valve chest above the main control valve) may be sticking. From the factory, they had an o-ring on them that tends to swell and cause problems after many years ( or exposure to diesel fuel). Mine had symptoms like yours for many years...gradually getting worse over time. When it finally quit lifting altogether, I found this valve stuck tight.

Good luck

Think I might go down the blocked filter route. If it was the unload valve sticking then it would normally jam the lift in the raise position. But I get the impression its not lifting from what Terry has said.

What sort of Auxillary chest have you got fitted Terry?

commander, the problem occurs in both draft and position control. Thanks for your suggestions, I will use them when I start to work on this problem.
Brian, the arms do not lift. If I leave the control lever in the up position when I park the tractor, they leak down over a couple of days and stay down until the tractor has run for about five minutes. Moving the control lever or the little lever under the seat makes no difference. The exhaust filter was replaced and the inlet screen cleaned in August but I will check them again when I next pull the top off the lift.
Under the seat, on top of the lift cover, is a black knob that is stuck.



The knob is plastic and is connected by linkage so that a small round disk on the control lever will move the linkage when it is moved all the way up. This linkage was completely froze when I got the tractor. I have the linkage working well but the knob will not turn at all. I believe this knob controls the flow of fluid to adjust the speed of the lift arm movement.
Thanks,
Terry

Terry, that is a flow control device. Given that it's stuck, I believe I'd start by removing it and trying to free it up. ..and check the operation of the flow control valve in the housing also.

Regards

I would check this first. The fact that the adjusting knob is stuck is not a major problem but the valve itself may be sticking. Take out the plug behind it and get the valve out. Polish it with a little metal polish, not abbrasive paper and try again.

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Terry,
the life clutch is for both life hydraulics and the PTO. Both are operated by the same axle. The second clutch allows changing gears without stopping any implement or the lift.

Just engage the PTO and check if that one is running.
When you put a high load (mower) on that PTO, does it continue turning ?

If this is ok, the hydraulics are to be checked :

Would start with the suction filter : clean / pressure of the pump / Flow control valve ...

Terry,
Are you sure there is plenty of oil in there? If not sure, maybe put in a few more litres, that might help. You'll know when there's enough, the lift will start coming up as you pour it in. I know when I had a leak in the back, and had lost quite a bit, it would take a few minutes for the lift to start rising- but if I topped it up while it was running, the lift would come up immediately.

My lift has now completely quit. The arms are all the way down and will not make any attempt to raise in either position or draft control.
Brian, I took the flow control device off and removed the roll pin that holds the flow control valve. But the plug would not come out. I tried soaking it with Liquid Wrench (penetrating oil) and tapping it with a hammer. I also tried heating it slightly. I did not want to use much heat as I was afraid heat might cause damage. The retaining plug never came out, so I don't know what condition the valve is in. I did manage to drive it in slightly, maybe one millimeter, while trying to break it free. If I take the roll pin out with the tractor back together will the hydraulic pressure from the pump push the valve out?
With the flow control device off the tractor, I cranked the engine with the stop switch pulled out. I got a good flow of oil from one of the ports that goes into the flow control device. So the pump appears to be working well.
I took the lift cover off and checked the linkage to the control valve. I believe the linkage is good and the control valve moves through out the range of travel of the main control lever.
So now I am thinking either the unload valve or the flow control valve is stuck "open". I am going now to study the manual to see how to proceed.
I did replace the O-rings and gasket in the flow control device while I had it off the tractor.
Terry

For anyone following this thread, reseaching or searching threads about this type of problem, Terry seems to have solved his problem and explained the results in a new thread here: http://www.fordsontractorpages.nl/phpbb ... =3178#3178

For anyone following this thread, reseaching or searching threads about this type of problem, Terry seems to have solved his problem and explained the results in a new thread here: http://www.fordsontractorpages.nl/phpbb ... =3178#3178 (thread ref corrrected)