Unload valve

[woodcutter]

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This is the valve out of my super major, does anyone know how tight it should be? I have cleaned it up and the bore but I can only just slide it back and forth using my thumb and pushing with a punch , should it slide as easy as the control valve? Any help appreciated

[Brian]

That is the unload valve AND bush that you have there. The unload valve itself looks like this:



This one has the later metal sealing ring rather than the "O" ring. The "O" ring is a special and not just any old one, it is one of the few items that I would recommend you got from CNH.

The bush should be a tight fit in the ram cylinder. It was pulled into place with a special tool. The unload valve should be a "firm" fit when the bush is in place with the "O" ring fitted.

At one time Ford recommended fitting the valve without an "O" ring to stop sticking valves and the valves hammering the plug out of the cylinder and breaking the two plate retaining bolts in the process.

[woodcutter]

So how do I remove valve from bush? And there are two little notches or cut outs on the bush does it matter where these go or are they for the special tool ? Cheers for the reply Brian

[Brian]

I would soak it in easing fluid then support the back of the bush with either copper or wood, not steel, to avoid damaging it then gently tap the domed end. If the valve is so stuck that the bush came out when you tried to get it out it is pretty well stuck. Be careful because the shaft of the valve can bend ever so slightly and then it will be no further use. You also do not want to put a bur on the edges of the bush.

The notches are to bleed oil out, the two large ones go to the rear as you replace the bush.

If your valve is that stuck it probably has a steel ring not an "O" ring and this has rusted to the bush. They are very fragile and easily broken when you replace the valve even with the special tool. I gently push the valve into the bush until it rests on the ring, then ease the ring into the bore with a small screwdriver at the same time gently pushing on the valve. I also apply a heavy coat of MS grease to the ring which helps hold it in place.

The bush may need a drop of Loctite to help hold it in place if it is a loose fit but do not get any on the inside.

The unload valve works at about 11 psi and this is maintained by the valve on the bottom of the return filter so check that the valve is there and the filter is OK.

[woodcutter]

We'll I fitted it all back together and it's still not right, when it starts to lift it keeps rising all the way till the arms stop you can't stop it half way, and when you try to drop the arms they won't unless you give the lift arms a jolt .

[Brian]

Your unload valve is still sticking, how did you get it out? Did you drive it out from the rear with a punch? If so you have possibly bent the shaft where it narrows. Even the slightest kink that you cannot see will give a problem. The other problem could be the control valve but from what you said earlier the control valve slides through the bush easily.

What sort of seal was on the unload valve? Was it a metal ring? If it was an "O" ring try leaving it off.

[woodcutter]

It was a rubber o ring, I tapped it out originally with a punch and the whole lot came out including bush. I tapped it out of the bush using a socket and cleaned it all up, it just didn't seem to slide nice a bit stiff but I wasn't sure how tight it needed to be, I guess it could be bent. Will a second hand valve fit? And would the unload valve cause it to keep rising?

[Brian]

Second hand valve will be fine and yes, this can cause your lifting problem. If this valve is not "shuttling" then the oil is locked in the ram cylinder and oil from the control valve is permanently diverted, giving you your constant lift.

Right back to the early 1950's when this design was used on tractors in the US, they all suffered from sticking unload valves, even the 1000nd series has the same problem so it is nothing new.

I always advise you do not drive the components out with any force other than a very light tap. Been there, got too cocky, done it, have the valve in my collection to remind me!

[woodcutter]

I was quite gentle, but I think I'm going to try and find a second hand valve, as I couldn't get it to slide nice. Don't know if you can buy them new? So if anyone got one they want to sell let me know. Cheers for all the help

[Brian]

Have you found a valve? If not, drop me an e-mail, I now have a couple of lifts I am breaking for parts.

[AdrianNPMajor]

Hello Brian
When you break the lifts, I wonder if you might have time to photograph the dismantling process and to give a master class on the subject. This could then become one of the locked topics at the top of the forum board. It's a bit of cheeky demand on your time, but I for one would find it a very valuable reference tool.
Best wishes
Adrian

[woodcutter]

No not found a valve yet I rang new holland but they not got back to me, how much do you want for valve including postage pm if you want cheers

[Brian]

£5.00 plus postage if that would be OK.

[woodcutter]

Il have that cheers send me details, I tried to message you but I can't .

[woodcutter]

I can't find away to contact you Brian and I don't know your email address

[woodcutter]

Have you found a valve? If not, drop me an e-mail, I now have a couple of lifts I am breaking for parts.

Hi Brian I don't know your email address, but I still want the valve if you have one, Id like to get the hydraulics working cheers

[Brian]

bhe at btconnect.com. Been a bit tied up so have not got the valve out yet. Should be out and on the way by Monday.

[woodcutter]

Thanks brian, valve arrived in post this morning so I cracked on and fitted it. I left the o-ring that it came with on, it looked in good condition, when the top was off I noticed the control valve was sticking so a bit more polishing put it together and it's all working like it should

[Dandy Dave]

Nice! Dandy Dave!

[woodcutter]

I had a local delivery of wood today so took the major all went well but a little bit of oil comes out of exhaust, but the previous owner hadn't used her for a while so hoping will clear up after a bit more use.

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