Deere 850 hydraulic problem, no flow.

JasG · May 27, 2008

A friends 850 hasn稚 been used to much in the last year. Mostly and hour or so every couple of weeks mainly just to run the thing. This weekend when we started it the machine had no hydraulics at all. The machine has a loader run with 2 remotes in the back and this and the 3 point hitch had no flow. Under the seat is where it appears the main valve that sends flow to the areas of the tractor is. Out the front of the valve seems to be the 電raft control. By screwing the flow control in and out we were able to get some flow going but still not like it should be to either the 3 point hitch or the loader. Any ideas on what could be wrong? Maybe a stuck by pass?

3 weeks ago the last time the machine was run everything seemed fine.

shot_gun · May 27, 2008

When the last time the sump screen was cleaned ? I have seen tractors that don't run alot get a sludge like alge that builds up on the sump sceen and choke the hyd. flow.

JasG · May 28, 2008

Thanks for the reply. Do not know and the owner has no idea where the screen is nor do I. Where is this screen located?

Even though the filter hasen't been on that long I'm going to change the main filter to see if that could be some of the problem.

shot_gun · May 28, 2008

If memory serves me correctly it should be on the left side of the transmission forward of the axle. It should be a 2-3 inch round with two bolts holding it on. Be prepared to drain the oil out. Once you open that door all the oil will drain. So drain the oil first so you don't have too much of a mess.

JasG · May 29, 2008

I'll look this weekend thank you for the information.

JasG · Jun 12, 2008

Just wanted to update my post. Some how the hydraulic fluid got water or something in it. I changed the filter and it came out milky colored. Changed the fluid and now it works the best it has in a long time.

This model has power steering and on these the filter is external spin on type. The arm strong models have the sump screen from what I was told. I had to go to the dealer to see if i had the correct filter. On this one I had to unbolt the bracket that holds the filter and drop it down to clear the back of the floor board. The NAPA filter it had on it was 1" shorter and fit on.

scott5155 · Nov 18, 2010

I go to a trade school where we have a 850 john deere where we can't determine the leak and been sitting for four year and finally got it running last month and filled it up with hydrolic fluid and it was gone with in a day and plus we had to put on a new hydrolic arm on the tractor because it was spitting out hydrolic fluid we put the new one on and it still leaks so i'm not sure if the part defective or not. I the only one in my trade school shop who has a mechanics background so I would be the only one fixing it and I tell telling them to send the tractor to have it looked at but they won't they say the tractors fine but I know it not and I know what's broken or need to be repair on it because I diagnose it. What should I do?...