3pth lifts by itself?

[uphere]

Ok - I've seen 3pth lower by themselves - but what would make them raise by themselves? I have a Howse 5ft bushhog on the back of a 2740 and if I have it raised half way it will (at idle) every 4 minutes raise itself slightly? If I have it raised all the way it is of course fine.

 

[k0ua]

It is leaking down, and the position control tries to raise it back..

James K0UA

 

[uphere]

That's what I wondered - but there is no leak ... I have been checking it for the last two months since it started doing this but the hydraulic fluid level is at the same level as it has been for the last year.

 

[uphere]

But there is no leak?

 

[k0ua]

The leak is internal, not out onto the ground, so the fluid is always still in the tank. I had an old Long 2360 that did it, after a few years.

James K0UA

 

[uphere]

Is this something "fixable" (if so, are we talking big $$$) - or is it something that I just live with?

 

[Guesseral]

This is most likley a worn set of O ring seals on the hydraulic piston, or a worn safety or control valve or at least that's the wat it was on older tractor hydraulic's. If it is only doing this every 4 minutes I wouldn't worry about it. My old jubilee did this and it looked like a jack in the box like every few seconds, I rebuilt it and the O rings on the piston were missing a piece of rubber. This tractor did that for years, but I knew nothing about hydraulics at the time so I just lived with it. This was an easy fix for one because I did it myself so it was cheep finding the parts was harder but not imposible. On the newer tractors lots of lets say stuff has to be removed making it an expensive project if someone else does it because they charge by the hour. Its not that hard if you get a service manual and have good mechanical sense, that's if you can get a service manual. But like I said I wouldn't worry about it at this point it's more of a nucience that anything else its probably just blow by on the piston. That's just my take on it others may think it needs to be corrected, not sure just how others would feel I only know what I have experienced in the past heck they could make them totally different now! Lets see what others say.

 

[JimmyBean]

My old Oliver 550 did it for 20 years and I never worried about it. I sold the tractor that way and it is still in service 6 years later. I agree it is just bypass at the cylinder or the valve and is more of a pain in the *** than a problem. It never failed to hold up an implement or anything serious. I know a newer tractor should not be doing this already but some of the smaller things like seals might not be as good as they should have been! My opinion only......lol.

 

[uphere]

Thanks lads (guesseral & jimmy) ... I can live with it - it just caught me a bit off guard .. in fact I had finishing hogging for the day, had put a beer down on the bush-hog (and before the tractor police come at me no it was stopped and the tractor was off ... and before you know it the bush-hog jumped up a very tiny bit but just enough to spill my beer. Now there are some things I can take - but that it not acceptable!!

 

[xtn]

Thanks lads (guesseral & jimmy) ... I can live with it - it just caught me a bit off guard .. in fact I had finishing hogging for the day, had put a beer down on the bush-hog (and before the tractor police come at me no it was stopped and the tractor was off ... and before you know it the bush-hog jumped up a very tiny bit but just enough to spill my beer. Now there are some things I can take - but that it not acceptable!!

I can't imagine how the position control could attempt to raise the 3pt with the tractor off. Can anybody enlighten me?

xtn

 

[Guesseral]

I think he is just trying to escape the rath of the tractor police, and neglected to mention the tractor was running!

 

[uphere]

ok ... before some smart@#$ responds - I had not had a beer yet.

I have had it happen before while it was running - but I am sure it moved a little (and I thought it went up) just after I had turned it off. I'll chaulk it up to old age (mine) and leave it as that.

 

[Guesseral]

Now now calm down just a little frendly digging going on. I myself drink my beer while I am running the tractor.........I thought that was why they installed the beer holder on the fender heck that was the largest selling point for me!

 

[uphere]

I know you guys are I must admit that ever since I changed the hydraulic fluid to a synthetic blend it seems to be a little too thin in the hot weather - but works excellent uphere when it is minus 40 degrees. I'll just have to stop working and start drinking more on the hot days!

 

[Guesseral]

Now there's a plan!

 

[Soundguy]

But there is no leak?

think inside the box

it's an internal leak in the lift circuit.. most usually from fluid leaking past the 3pt piston back into the hyds sump.. after it leaks a lil, the circuit regenerates if it is a position control feedback system.

soundguy

 

[EE_Bota]

It is possible for it to appear to go up, after first coming down. Lots of times, there is mechanical hysteresis, and a "pop" or "thud" will be heard when it drops, and after it drops, a bit of momentum pushed the tires down in the back, lightens them in the front, and as the stored energy in the tires and the linkages recover, it will go up.

The best solution for the problem is to not put a beer on a bushhog.

 

[uphere]

Thanks guys ... I knew I should have bought "light" beer!