Hydraulic issues

[Gary T72]

I have a small JD 850 tractor with a Bushog front loader. I purchased it used and changed the hydraulic oil and filter. The oil that was in it looked like coffee with a lot of cream in it which I assume means some water got in there. The oil now looks good but I have always had a problem with the 3 point hitch jumping up and down when trying to adjust it. Recently one of the front loader cylinders was dripping oil so I had it rebuilt. The guy at the hydraulic shop told me there was no need to bleed it, just to work the bucket up and own etc. and it would be fine which initially appeared to be the case. Now when the tractor gets an hour or so use the bucket operation is jerky and the 3 point issue is no better. I know there is a valve knob and a lever under the seat that have something to do with the hydraulics but I don't know at this point where to start on this problem. Thanks to anyone/everyone that can help me.

 

[jenkinsph]

The valve under the seat is used to adjust the rate of drop for the 3pt hitch, if your implement drops too quickly you can tighten/close down this know to make the implement drop slower. Opening the valve up for light implements such as an emoty spin spreader, if you tighten it up all the way the hitch will stay in the raised position. This valve does not have any affect on the raising speed of the hitch, only the drop rate.

About the jerky hitch, could be several things but I would check for an air leak on the pump suction side and check to see if you have a screen on the pump suction that was not cleaned when you changed the fluid and filter. Most of the Deere's had a suction screen but I don't know about the 850.

 

[Leejohn]

My 950 had a small red lever under the seat that had something to to do with the 3pt, just can't remember what. If it was moved one way the oil would heat up. I think I ran it pointing stright up. See if you can find one on your tractor, it's only about 1" or 1 1/2" long.
Maybe Txjim well see this,he knows alot about the JD's