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Fordson Supermajor hydraulic problem

Posted: Sun Feb 20, 2011 4:21 am
by birmanfan
I have a 1963 DKN Supermajor and the hydraulics are slow to lift and there is no lift and hold. The hold position is not working. You've got to have it continuously in lift to travel or pull the auxilliary from in front of and below the seat that works the hydraulics for a tip trailer, by pulling that out and then lowering the hydraulic lever down to lower is the only way I can travel to ensure the blade will not come down. When I am operating the tractor, using the grader blade, and having it in the lift position all the time to keep it up, you can stop the tractor and it will just lower to the ground on its own. Any advice to fix this problem would be great. This has all the draft control on the hydraulics.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Feb 20, 2011 11:36 am
by Emiel
Hello,

That sounds very dangerous to me. Your tractor is operating in draft control mode. You should switch to position control. There should be a short lever on the right hand side of the lift cover which you can turn 90 degrees to set it from draft to position control. If that is impossible, then you have to investigate further.

Regards

Emiel

Re: Fordson Supermajor hydraulic problem

Posted: Mon Feb 21, 2011 3:26 pm
by cwayne
I feel certain that your problem is either the unloading valve or the hdraulic piston gland /cylinder. For it to leak down that fast I would suspect the unloader valve to be stuck in the open position, if you find this to be the cause I would also inspect the lift cylinder and gland while you have it apart, as it has been many years probably a lot of moisture and a lot of lifts on the unit .
By all means get a service manual ( if you do not already have one ) before attempting the repair.Image

Re: Fordson Supermajor hydraulic problem

Posted: Tue Feb 22, 2011 5:04 am
by JC
Here's a link to Brian's answer to a similar problem on the old BB.
http://www.fordsontractorpages.nl/ubb/F ... 00730.html

Re: Fordson Supermajor hydraulic problem

Posted: Thu Feb 24, 2011 12:15 pm
by icom102
i am also having the same problem i have been told i need a new unloading vlave can they be got anywhere?

Re: Fordson Supermajor hydraulic problem

Posted: Thu Feb 24, 2011 12:21 pm
by icom102
whats a relief valve?

Re: Fordson Supermajor hydraulic problem

Posted: Thu Feb 24, 2011 1:55 pm
by Aussie Frank
Hi Icom.

All hydaulic systems need a relief valve. It's function is to limit the maximum pressure that the hydraulic pump gets to. If you don't have one the pressure of the hydraulics would rise to the point of explosion when a cylinder gets to the end of travel or a valve gets shut off.

I have seen people mess with the settings on hydraulic log splitters trying to get a little more power out of them by increasing the relief valve pressure only to have the pump split gears, have the motor twist off shafts or hoses explode.

In my opinion the relief valve is the most important item in any hydraulic system. A leaking one will stop the hydralics having any power and a stuck one will make something else break.

Regards, Frank.

Re: Fordson Supermajor hydraulic problem

Posted: Thu Feb 24, 2011 2:06 pm
by icom102
so there is a relief valve and a unloading valve or are both the same thing?

Re: Fordson Supermajor hydraulic problem

Posted: Thu Feb 24, 2011 10:44 pm
by Aussie Frank
Hi Icom,

Relief valve is a general term used in hydraulic systems for the valve that limits the maximum pressure. In the case of the Fordson lift the name given to the valve that performs this function is the Unloading valve if my understanding of the lift hydraulics is correct. My knowledge of the Fordson lift is limited so I may be wrong on this, but I do not believe there is a separate relief valve.

Regards, Frank.

Re: Fordson Supermajor hydraulic problem

Posted: Fri Feb 25, 2011 8:02 am
by henk
The other one is the unloading valve I think.
Does anyone know how that one works? I'm don't have much knowledge about hydraulics. How does the lever works that operates the lift? Have to work on it this weekend because my lift is dropping fast with the plough in it.

Re: Fordson Supermajor hydraulic problem

Posted: Fri Feb 25, 2011 8:36 am
by JC
You're right Frank. The relief valve is called the unloading valve. The check valve is called the non-return valve.

Henk, Your problem sounds like the non-return valve instead of the unloading valve. If its not dropping too fast, it could be piston and cylinder seals.

icom102, I think that unloading valves are available for the Super Major, but your lift is from a Major and I haven't found any place that sells unloading valves for them.

Re: Fordson Supermajor hydraulic problem

Posted: Fri Feb 25, 2011 1:13 pm
by henk
henk wrote:The other one is the unloading valve I think.
I ment the non return.
The technical Englisch and the different names is very confiusing.

The piston and seals are perfect.
I have put a shim under the unloading valve and the problem was half gone.
I'm planning to measure the pressure and than remove the unit. Than remove both valves and hone them.

Re: Fordson Supermajor hydraulic problem

Posted: Sat Feb 26, 2011 10:47 pm
by henk
I have done some work on the hydraulics of my new major today. With no success.
There has been some topics about this subject over the years on all three boards but none was salved as far as I could remember.
In an attempt to get things straighten for me and other folks that are having the same problem I will describe what I have done so far and post some pictures. Maybe together we can solve this one.

Two years ago my lift was lowering slowly. It was bothering me because of my fertilizer that was dropping. My guess was that it was the piston gland (seal). I removed it and it looked fine, but I renewed the gland. Nothing changed.
Then I removed the valve body again and checked the two valves inside it. They seem ok to me.
After I have used a cultivator for some time the problem went worse. I could not hold up the plow.
I have put a washer on top of the unloading (relief) valve and the plow was now going down very slowly. That gave me the idea it was the unloading valve.
I plugged in a pressure gauge and with the first setting the pump gave 200 bar pressure but it dropped right after I stopped pumping. I placed the washer again and the pressure went up to 225 bar and dropped also but very slowly. The pressure should be 150 bar.
I removed the valve body again and removed both valves again. I could not find anything wrong with them.
Nevertheless I honed them both on each other with some grinding pasta. (400). I renewed the o-ring on the unloading valve seat. The book say it should be a 0.375ā€ x 0.07ā€ o-ring. That would mean 9.5 mm x 1.75 mm. I have used before a 10 mm x 1.75 mm one. Now I have replaced it by a 10 mm x 2 mm because the grove is 2.5 mm width.
I rebuild everything and placed it back on the lift cover.
Pressure was now 200 bar and going down fast. With the washer on it pressure was 225 bar and going down just as fast. Seemed the problem was worse.

Questions:
I know how the unloading valve works, but how does the non return (check) valve work?
Could the piston valve have anything to do with it?

Now some pictures.

Image
Relief valve

Image
Relief valve seat with the 1.75 mm o-ring

Image
Relief valve top

Image
Grinding the relief valve

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Non return valve seat

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Non return valve complete

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Non return valve top

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Piston valve

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Piston valve

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Pressure gauge

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Piston gland

Re: Fordson Supermajor hydraulic problem

Posted: Sun Feb 27, 2011 1:07 pm
by henk
Am I right to assume that once the lift is in the upper position, the oil is locked between the ram cylinder piston and the relief valve and the non return valve. Or is there a fourth place were the oil can pass?
How does the thickness of the oil affects the leaking of the oil?.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Feb 27, 2011 7:34 pm
by henk
The fourth place would be the o-ring inside the cylinde of the liftcover.

Image

Re: Fordson Supermajor hydraulic problem

Posted: Sun Feb 27, 2011 9:32 pm
by Supermanuel
To understand the hydraulics first thing is to know if it is Super or np Super. All older ones have a totally different system. Short description of various valves and their function. I.e. This description is only for Super.

Relief valve is on Super either short or long version. Long for np. They don't work the same way. The short valve, when it once opens, drops the pressure to abt. 20 bar and returns to normal mode only after the load has been removed. Use low rpm to avoid it. The pressure is limited to 175 bar. To put coin behind the spring only helps to blow the pump body. The long np valve does not drop the pressure when it opens. The valves are interchangeable. This valve points forward and is visible under seat.

Unloading valve is in the lift cylinder housing and has nothing to do with relief valve. Main trouble of this valve is that it binds. Then the hydraulics don't lift at all. The valve can be removed either with a 8 mm pin and hammer or with sledge hammer having thread 3/8 UNF from the other end. Clean the valve and remove O-ring. A common reason why Super does not lift at all..

Check valve is near relief valve and can be removed without lifting the cover. If it is leaking the arms are dropping faster but should not reduce lifting power. It co-operates with the unloading valve. May be damaged if overtightened especially on np. Special tools may be needed to dismantle it. Oil is passing it on the way to lift cylinder when unloading valve is in lifting position.

Qualitrol lever should point forward.

Possible reasons for lack of power.
Short relief valve has opened and the load is still on.
System is leaking. Check pressure.
Lift piston seal leaking.
Somewhere leaking O-rings. (Between pump and cover or anywhere in the system.)
Leaking safety valve at lift cylinder.
Binding control valve.
Pump body broken.
Bent or damaged linkage inside the lifting cover.

First thing to check is pressure. After that it is possible to find the reason. Before measuring pressure remove all coins from relief valve.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Feb 27, 2011 9:38 pm
by henk
Thank you Supermanuel,

I hope this will help the folks with a Super Major.
Would be nice to find someone who has the same knowledge about the New and Power setup.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Mar 06, 2011 5:32 pm
by henk
Been working on the hydraulics again this weekend.
The honing with the drilling machine at the picture was no succes. So this week I did the same job at a lathe. But I notice that the cub was not round. That made is hard to hone it correctly.
It is possible to hone it in the unit. Just put the lower part in it's place and drop the cub with some hone pasta in. The cub can't move in the hole. Than put the spring in the cub and use a battery screwdriver to turn is.
I made a device were I can put in the unloading valve and that is guide by the hole. The device can be turned by the battery screwdriver.
The result was better. I removed a washer from the relief valve.
Result: 180 bar pressure and going down slowly.
After I mounted the plow: pressure was going down slow and stopped at 60 bar and than the plow was going down very slow.
This convinced me that the relief valve is the trouble maker.
I hope to do some more work on it this week.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Mar 06, 2011 6:13 pm
by JC
Henk,
I think that if you are getting that much pressure, your unload valve is working. Do you have any pictures of it after you honed it?

I looked at the picture of your piston, and it has a lot of scratches. Does the inside of the cylinder look the same? If so, that's probably where the problem is.

Re: Fordson Supermajor hydraulic problem

Posted: Sun Mar 06, 2011 7:43 pm
by henk
JC,

The piston is grooved but the cylinder is not. There's a bit of pit rust at the end but that does not affect the leaking as the gland is not going through that part.
The honing of the valve has been too much now. So I have to grind some of on a precision grinding machine or find another one. I forgot to take some picture. Planning to set the valve at 150 bar and see what will happen. That's the pressure according to the book.

Re: Fordson Supermajor hydraulic problem

Posted: Mon Mar 07, 2011 8:19 pm
by Supermanuel
After I looked at your photos, I saw that you have the New Major hydraulics, not Super.

Re: Fordson Supermajor hydraulic problem

Posted: Tue Mar 08, 2011 12:06 pm
by henk
Supermanuel,

The name of this topic assumes that it's a super system, but birmanfan who started this topic has a super model with a power lift cover.

Re: Fordson Supermajor hydraulic problem

Posted: Tue Apr 05, 2011 6:55 pm
by henk
Been working on the system again.

I have the relief valve cub grinded on a machine. After that I honed the relief valve the way it should be done. I was doing it wrong. Gave the unloading valve the same treatment with some special tools to guide it.
After rebuild and with only one sim I had 160 bar pressure, but it was dropping slowly. After I put the first setup with the simrings back pressure was 210 bar as first but was dropping the same speed.

I almoost conficed that both valves are ok. Piston seal is also ok.
To find out if it is the hydraulic unit ore other components I'm looking for another one, so I can see in what part of the system the problem is located.

Here some pictures from the honing of the valves.
http://www.mijnalbum.nl/Album=RWFNVYU3

Re: Fordson Supermajor hydraulic problem

Posted: Sun Jul 03, 2011 11:55 am
by henk
I found a second unit, complete with piston and cylinder. Cleaned it up.
First I changed the piston and cylinder and put a new O-ring in. Same result.
Then changed the piston of the quadrant. Same result.
Then changed the whole hydraulic unit. Same result.
Made a new tool to hone the unloading valve. After that the grove in the valve was to deep and I had to let it grind.
This week the guy that would grind my unloading valve was on leave again an grinded the valve.
I honed the valve until I had a good closing. Place the hydraulic unit on the major yesterday after I changed all the paper sealing and O-rings. The pressure was still going down, but much slower than first.
So I think that the relief valve, and the unloading valve were both leaking.
Question is now, what is still leaking. Could it be the quadrant piston?
Any ideas how to handle that.

Now Iā€™m going to rebuild the second unit to see if there are any difference in parts and check the valves.

Re: Fordson Supermajor hydraulic problem

Posted: Sun May 24, 2015 8:54 am
by Stu_Fletch
Hello Henk did you ever manage to resolve this issue?

Cheers