The Fordson Tractor Pages Forum

The hydraulic arms drops very quickly after lifting them on my 1959 major .I assume that's the big seal on the piston, my question is that when I raise the arms up and if I hold them up oil leaks out of the two flat plates beneath the front of the seat. I've opened up the two 10 mm studs to find a spring and a washer on top and bottom of the spring . I assume this is a release valve . But why is if leaking out of the little flat plates ??ive put gasket cement on and refitted the spring and plates but it still leaked . What's causing this ?
Paudie

Normaly it's enough to use a paper sealing. Is there a crack in the plates?

I too am suffering from hydraulic arms dropping after a few minutes of them being raised (with or without implement) on my 1955 Major. There is no visible oil leaking and the hydraulics have no problem lifting weight. The oil has been renewed, is of the correct type and quantity. Could this be cured by replacing seals in the pump / piston? Thank you, in advance!

You could check the piston gland and cylinder with the O-ring in the rear end cover.
I've been trying to fix that problem for many times. There are a few topics about it. http://www.fordsontractorpages.nl/phpbb ... =hydraulic
Mine is still not working well and going down in about 10 minutes whit a load.
I think it’s the piston and it’s hole in the hydraulic unit at the front.
Wondering if there’s something to fix the groves in the hole.

Hey, easy start ( love the name lol) it sounds like your piston seals are worn like henk said. I have took the seat and hydraulic top /cover of since my previous post and found that all the seals were in poor condition, so I replaced them all. It's a very easy job to do . I bought the seals in a local good Agri store for €20. I will need a hand to lift it back on to the tractor , so I'll keep ye posted as to what happens , fingers crossed. I read some where that the older majors were never really designed to keep the arms up indefinitely ,
Paudie

You do not need to take the lift off to re-seal the piston, everything comes out of the front when you take the valve chest off. Check out the Wiki now it is back and working ( code "fordsontractorpages" password "dotty") there are pictures there of the lift and seals. The piston seal is a strange size so watch out if you are buying a standard seal. My supplier, Allseals of Norwich, made me a seal of special hard wearing material for the cost of £11.00 inc Vat.

http://www.fordsontractorpages.nl/wiki/ ... epair.html

Thank you for all the replies! I too will update this thread once I have located and rectified the cause!

As promised my update is that I've just put the hydraulic valve chest top back on my FMD and thankfully everything is working very well and the lift arms are not dropping at all . But my original problem still stands ??!! if I lift the hydraulic arms up to the top and hold them there so the pump is constantly pumping the oil comes out the top of the valve chest, it comes out the brake side of the chest.?has anyone experienced this before , any thoughts on this would be helpful .
Regards Paudie

Have you checked the pump pressure. The valve that is leaking is the unload valve which gets shimmed up to increase the pressure, I wonder if there are too many "shims" in there so that the plate is not sitting down on the valve chest. As Henk says, it is only a paper gasket and there should not be a lot of pressure there.

We used to find the old sixpence coin used as a shim.

Well I'll give the reduction of the shims a try thanks ,when I get this injector pump sorted, And the tractor up and running again, I'm tempted to just get a new seal in the injector pump and leave the bearings alone as per my recent post ?
Thanks again lads

You are getting into problem areas if you go into the pump without the proper tools. Even replacing the bearings would mean the need for a pump recalibration to be sure of not creating further problems so I would stick by just replacing the seal. I have said it many times before, I am trained in the repair of pumps and even so would not tackle any repairs without the complete dust proof room and calibration equipment.

Thanks Brian ,I think your right I'll leave well enough alone with the injector pump bearings, thanks again lads

If however you decide to let someone change the bearings, the type of the bearings is E20.