860 hyd leaks down, and maybe a solution.

For those of you that haven't read my earlier thread, I'll give a very brief history. My 860's hydraulic system had problems. If I shut off the engine with the lift in the up position while there was an implement attached to it, it would leak down to the ground in about 9 or 10 minutes. The lift would work properly when I restarted the tractor. If I put the lift in the down position and shut off the tractor, the lift arms would not even try to lift and I would have to bleed air from the pump and then from the remote on top of the lift plate. In both senarios the lift would raise in a jerky motion.

I asked for some advice and help on this board and got some very good responses. Based on those responses I purchased an O-ring kit for the lift plate, and replaced all of them that I could. I did NOT tamper with the valve located inside the cylinder housing. Is this the unloader valve? I'm not sure. I drained the fluid and cleaned out the reservior. I then refilled it with 134 fluid from the NH dearler. I did all of this at the same time, and nothing changed, the lift would still malfunction.

I then replaced the Safety Vavle. It's the one located under the accessory cover on the lift plate, according to my NH dealer. I asked for a check valve. They didn't know what I was talking about. So looking at their pc with an exploded view, I pointed it out to them. They said that was called the Safety Valve. Anyway, I replaced that, and still there was no improvement.

Today I loaded it on the trailer to take it to a friend's house to do a little bit of bushhogging. While it was sitting on the trailer idling, I noticed a fluid leak that had never been there before. This tractor had no leaks prior to this one. Well, it was leaking from the spool on the remote accessory plate. I shut off the tractor, removed the spool and saw what appeared to be an o-ring groove, but there was no o-ring there. I went to the store, bought an 0-ring, installed it, and guess what? It has now been about 8hrs and the lift has dropped only about 3 inches. The o-ring that I installed was not the right size. It did not fit on the OD of the spool, and it was too big for the ID of the housing. So I assume that it is compessed somewhat and thus sealed on the spool. I will however get the proper one tomorrow and hope it cure the lift 100%.

If it doesn't, I'll ask for more advice.

Thanks for listening, and I hope that this might help someone else diagnose his hydraulic lift woes.

Gil

The Safety Valve was in fact defective but because it was bleeding fluid the pressure didn't get high enough to push fluid past the spool on the remote, therefore that leak never manifested itself.

But after I replaced the Safety Valve, then there was sufficient pressure push the fluid past the spool?

Guys this is just a thought. Let me know what you hydraulic gurus think.

Gil