The Fordson Tractor Pages Forum

Hi
My 1960 dexta, dual clutch is fitted with a front loader fed off the auxillary circuit with another secondary valve that directs flow to either front loader or rear appliance if fitted/ used.
Problem is when using the loader with the the rear arms just drop - which is a pain as i have just made a very large concrete weight. Its not the load on the arms as they drop with or without the weight. This happens in both draft and position control.
looked at earlier posts but got confused. i can lock the loader in position by using the second valve in a neutral position which presumably just shuts off the return flow.


Regards

Mike,
If you are taking the oil for the loader from the Auxiliary Service Chest and have the knob pulled out, you have isolated everything from the ram cylinder so your dropping is caused by a leaking piston seal.

Never, never, never put your lift in Position control when you are using a loader or tipping trailer! In the situation you are in at the moment, if you select Position control and the lift arms drop, the internal linkage will put the valve into the raise position to try and bring the lift back up. But the ASC is diverting oil to the loader and that's where it will go. Even with the control lever in the fully lowered position the loader will continue to raise! This can be quite embarrassing. Take it from a person who Tipped a trailer carrying scenery for the local amateur drama group in the middle of the road in the market square.

is that piston in the control head or something deeper inside? I have heeded your warning about position control from previous postings.
Regards

Mike,

You have to take the top off and the ram cylinder off to get to the piston. The biggest job is getting the top off and that is not too bad.

Brian wrote:Mike,

Never, never, never put your lift in Position control when you are using a loader or tipping trailer! In the situation you are in at the moment, if you select Position control and the lift arms drop, the internal linkage will put the valve into the raise position to try and bring the lift back up.

Don't you mean draft control Brian?

No. Draft control is affected by pressure on the top link. Position control is affected by the position of the lift arms.

Although you COULD get pressure on the top link when using the auxiliary service port it is far more likely that the lift arms will drop and put the cycle into raise.

I have seen it happen many times, we had one customer who tipped a trailer load of grain on the main road amongst the holiday traffic! Thats why my little episode with the scenery was so embarrassing. I had to work out why his tractor had done it.

Right, thanks, I was thinking it was something to do with the top link. That's my second lesson for the day. So always have it in draft when using the auxiliary.
My other lesson came from some interesing reading about DIY zinc-electroplating of steel. It's quite a simple process, and easy to get good results.

thanks Brian -looks like its time to get the spanners out - anyone know if the seal/ o ring ( if thats what it is) is a standard part and where i can get one?
Thought i might as get one first before i take the head off,

regards

Mike,

When I did the one on Henrietta I took the seal to a hydraulics company and they made me one for £11.00.

It will be a lipped seal on the Dexta and may still be available from Case NewHolland but be careful, they may try to give you the "O" ring and leather backing washer for the later series.

Brian - excuse my ignorance but i presume you mean the large piston/ ram connected to the external top link?

I see Agriline do a seal and back up ring at about £5each which seams ok

Mike,
The ram is not connected to the top link, it works on a rocker that is splined to the lift arms.

I do not know the seal Agriline are offering but the Dexta does NOT have an "O" ring and back up washer, it has a proper seal with a lip.

The Ford 3000 has an "O" ring and backup washer but that is not a Dexta. You may have to buy a new piston if that is all being offered but a proper seal can be obtained from any company that does hydraulic ram parts. Just take your piston and old seal along to them.

Brian
I ordered the seal set from Agriline - it appears it is the later kit you describe a seal and leather back up not the correct atricle.

I thought i would have a look at the seal on a spare head i have and that turned out to be an o ring with a back up seal (leather i think). The piston on the tractor did have a single seal as you said.

Can i ask why you don't seem to like the idea of the seal & leather washer or indeed the later o ring type. Is it just because of authenticity or is there a practical/technical reason? Mine are working tractors so i am not to fussed i just want the thing to work.

That aside because i had the kit and the head was off i decided i might as well try the seals anyway. Main seal went on ok but the leather back up did not want to fit without stretching after which it just flopped about in the groove and there was no way it was going to fit back in the cylinder. Is there a secret to getting them on without stretching or so they shrink back??

I just put it back together without it as i had to do some hedgecutting with a maconnel finger bar hedgetrimmer i have. No surprise that although much better it still drops slowley when using the auxillary control to operate the hedgecutter rams. So back to the drawing board for me.

As i have previously outlined on other posts i am no mechanic so what is a stepped seal as a matter of interest. i have no idea how to get one should i take the piston in to a specialist or will measurments do. Should it fill the whole groove?

The Dexta piston was not designed to take a leather seal and "O" ring where as the 3000 was. It was a different seal groove and the "O" ring and seal fitted tightly together. The seal groove in the Dexta is wide compared to the later model and the ring and leather seal will wander about in it.

You need to soak the leather seal in oil before trying to fit it. It will stretch but with the "O" ring tight in the groove it holds in place then you have to force them into the ram cylinder with a hammer shaft and feeler gauge if you don't have the correct fitting tool.

If you had a 3000 piston the seals would work and the piston would fit in the Dexta.