JD 850 hydraulic problem

[Ronzoni]

I have JD 850 mini tractor with backhoe and loader. Recently the backhoe jammed up and fluid started oozing out of seals everywhere and pump starting squealing. It was like too much hydraulic fluid was driven into the controls and overwhelmed them.

Disconnected the backhoe and tried the loader and it squealed ONLY when not using. Worked fine up and down and bucket but squeals as soon as I stopped.

My guess is relief valve may be stuck or blocked.

I drained fluid, cleaned filter, replaced fluid and still no change. Where is the relief valve located? Am I guessing along the correct line?

 

[texasranger556]

Sounds like something is blocking the return path to sump. When you activate the loader function you're diverting the oil before it goes out the power beyond port of the loader valve.

Does the three point hitch work? Is the 3 point hitch lever stuck in the up position?

 

[Ronzoni]

The three point hitch normally works but I didn't check it recently. I will check that.

It looks like I must have bumped the three point hitch lever and one little move forward a hair and it shut up. Thanks. I'll see if that solves the back hoe also.

looks like I have to lengthen the stop.

 

[Ronzoni]

Ok thanks folks. All it was is the control stop on the radius wasn't positioned well enough to prevent accidentally engaging it beyond stop. Easy fix.

 

[texasranger556]

Nice!

 

[Jack Murdock]

Ronzoni,

Would you mind sending pictures ? I have the same tractor, similar issues but am not sure what the control stop is that you are referring to. Is it the stop on the 3 PT lever ?

Thanks in advance I have my 850 all apart for service currently but am reassembling tomorrow.

 

[beenthere]

All it was is the control stop on the radius

Likely yes, to the stop on the "radius", also referred to as the "quadrant" I believe.

 

[wsguerin]

Jack (and Ronzoni)

How do you do? I too have an 850 circa 1986 with the power steering kit and #75 loader. Jack, I also see you are in Stephentown, we rode the short but lovely Corkscrew trail a few weeks ago! We're in Germantown. Anyway, you both seem many levels beyond me in understanding these finicky beasts. My hydraulics are currently all out and oddly, they died just after I did a full screen-cleaning and oil change (did not change the canister filter as it is pretty new.) I have CONSTANT problems with white gunk build up in the transmission case which clogs the screen. Anyway, I just got a replacement Modular Controls Diverter valve ($300 form Worthington Tractor Parts in MI) and hope that fixes the bucket, steering, and 3-point, we'll see. The clue I'm following was that my power steering was slowly going out. The next step is what? The hydraulic pump?

 

[JimRB]

White gunk is often water/condensate. Is the tractor stored under a roof? Does the tractor ever do hot work like mowing pastures for a few hours? I call it hot work because my JD870 gets a nice hot transmission after a few hours of mowing that helps evaporate condensation. A friend got a MF135 years ago that had been semi-refurbed. I guess that means washed. We redid some bearings in the steering column, put on a new rubber boot for the gear shift and changed the milky white transmission lube. That transmission used regular gear oil like in a trucks rear end, not hydraulic fluid. Tractor is now stored in a shed. MY JD has been in the yard for 23 years but it gets good and hot at least a few times over the summer when mowing pastures. You should change the filter as it could be clogged up with that gunk.