Power Major Hydraulics

Gman · Post by **Gman** » Wed Jul 22, 2009 5:00 pm

Hello everyone, hope all is well. I freed up my controls on the hydraulics and all seemed ok but had not really put it to any heavy lifting until yesterday. With a boom pole attached I picked up my old box blade out of the woods, picked it up with no problem. Because it was swinging about I stopped and lowered to ground, then raised back up and when it reached top I think I heard a little pop noise from valve control housing. After this lift could not raise weight of box and without weight lifts were much slower and does not make same sound when reaching top. It would still raise and stayed up. Thinking maybe pressure relief valve. Any suggestions on where to start on trying to solve problem. As always your help is greatly appreciated.
Gerald[/img]

Post by **Brian** » Wed Jul 22, 2009 9:12 pm

When you lift a load on the Power Major hydraulics and it is too heavy or it reaches the top, then the unload valve opens and dumps the pressure oil back to tank. That is the "pop" or "click" you hear. The control lever then has to be returned to neutral before the valve will re-seat and give you pressure to lift again.

I would suspect that your Major may have had a rusted valve and the heavy load has unstuck it for you. It has now freed off and is working at a lower pressure than it was before. It is possible to shim the valve to get more pressure but it needs to be done with a pressure gauge fitted to avoid problems with the main hydraulic pump.

It is also possible that, if the valve was rusted, it cannot move freely in its sleeve and is not reseating to give full pressure. It would be a good idea to remove the two plates on the top of your lift control valve and check the sorings and the free movement of the valves beneath them.

Gman · Post by **Gman** » Wed Jul 22, 2009 9:53 pm

Thanks Brian. It did sit for some years and I did have to free up valve spool. Good chance rust is also on upload valve. Thinking I should try to get seals and o rings and see if I can repair all. Not sure if I'm ready or smart enough to do this. Have been reading other postings and going to Wiki for all the info I can find before attempting. I will remove the two plates on top and see what is there. I'm going to try and get a pic on here if I can figure that out also. Again thanks so much for your help.
Gerald

Gman · Post by **Gman** » Fri Jul 24, 2009 2:30 pm

Hey Brian, I've taken off retainer plates and with a little work was able to get spring guide, spring and valve retainer out. Valve was stuck, I still had lifts up and lowered and could see fluid flow through, thinking this indicates it was stuck open a little. The bore looks good and I see the ball laying in bottom of bore so have to get it out, thinking maybe a magnet will pick it up. Two shims in spring guide. On the drawings I have shows o rings on top of spring guide and sealing plugs but did not find any when removing top plates, just a gasket. I'm going to parts list to see if I can find out size of o rings and do they just sit on top because do not see any groves for them to seat in? Should the sealing plugs also be free and come out? As to the ball, can I replace it into valve seat instead of trying to keep it stuck to valve as I lower it back in? I see a little rust, how do you recommend cleaning, didn't think I should do any sanding. The only gasket material I have found is rubber or cork, what is there is more of a thin paper type gasket, any recommendation there? I'm sorry for all the questions but without your help would not be to this point of getting her back up and running, guess I need to send you a check.
Thank you so much for the help.
Gerald

Post by **Brian** » Fri Jul 24, 2009 3:37 pm

Sounds like you have found another little problem. You have the latest type valve and there should be no "O" rings just the paper gasket. No problem with the ball in the seat rather than on the end of the valve but make sure it is on the seat and not to one side.

You may find that a little bit of diesel or paraffin on the valve, a stick of wood where the spring fits and then spin it round between the fingers like grinding in valves, will clean things of rust. If not, a little metal polish or chrome cleaner will do.

You may need a slightly larger shim but thin washers can be used, don't put too many in though as you could burst the pump.

Gman · Post by **Gman** » Fri Jul 24, 2009 5:00 pm

Thanks Brian, just back from store, did find some paper type gasket material and also some o rings which may need on other areas as I work on her. As to the sealing plugs, should they be free and come out? With luck may be able to turn up some dirt this weekend, can't wait to smell that fresh dirt. If I figure out how to get a pic on here will try and get one posted. Thanks again so much, I'm sure I'll be asking more questions.
G

Gman · Post by **Gman** » Mon Jul 27, 2009 3:18 pm

Hey Brian, thanks for all your info. Looks like I'm going to pull the whole valve chest off and see what is there since cleaning unload valve did not seem to help. Guess I will try to look at non-return valve, o ring on pipe and ram cylinder. I looked to order a seal for ram cylinder and there was a 2" and a 3" choice, any idea as to size for a 11/1959 power major. I believe I also will need o ring for ram cylinder. I have read other posts and do believe I can remove valve chest, any suggestions before I start this. She still has good power, pulled a good size tree up a hill out of the woods without any trouble.
Thanks
Gerald

henk · Post by **henk** » Mon Jul 27, 2009 7:57 pm

Hello Gman,

Did you read this topic?
http://www.fordsontractorpages.nl/phpbb ... .php?t=763
It’s not easy to find the problem and fix it. I have stopped looking for the answer.

So it's still not working correct on my major. Maybe this winter I will look into it again.
I think you need the 3" seal.

Gman · Post by **Gman** » Mon Jul 27, 2009 8:22 pm

Thanks Henk, yea I'm getting tried of working on her, I want her to work for me. I will try the site, just ordered seals and o rings from yesterday tractor, hoping I ordered right ones. According to one catolog the power major has the smaller cylinder, so guess I'll find out when I pull it apart. Again thanks to everyone for all the help. I have been reading some of the other posts, I'm not a mechanic so we'll see.
Thanks
Gerald