deere 850 3 point won't raise

[tbrown850]

I have a 1988 850 with power steering. The power steering is working good but the three point will not raise. I noticed today that it will raise a small amount when the tractor starts. Otherwise it will only lower. I tried adjusting the little red lever under the seat. All the linkage appears to be moving correctly. When the steering is moved to full lock you can hear it load the engine. I have ordered a service manual, operator manual and I&t manual. Was hoping for some tips in the meantime. Thanks

 

[Tx Jim]

How long since hyd filter was changed?

 

[tbrown850]

How long since hyd filter was changed?

Not sure, just got the tractor. The odd thing is that power steering works perfect.

 

[Tx Jim]

I was taught to always try the easiest things 1st. I'm not sure if 850 has a steering priority valve such as the larger tractors have. I looked in parts catalog but was unable to locate one.

 

[tbrown850]

It almost seems like a priority valve or relief valve problem.

 

[lilburr]

I am currently going thru same problems with my recently purchased JD850 ('79, me thinks), no power steering. I have cleaned the screen, changed out the hyd fluid twice and it still gets lazy after just a little use. I'm fixing to change it out again. On mine, I get a noise in the case when clutch is released; I'm thinking here lately that its the hyd pump making the racket. It sorta chatters as it is trying to raise - and slowly, it does raise although not to the finished height.

I started a thread on the JD section several months back, I will find it and post it here although i have broadened the topic of the thread since I started it. I got the manuals and some info but kinda disappointed with them. Hyd pressure gauge is suggested to measure pressures and act from these numbers but I have not. Maybe next step for me before changing out fluid again and cleaning screen. Pump is $$$.

i found it: http://www.tractorbynet.com/forums/...ng/292972-850-3-point-problem.html?highlight=

 

[tbrown850]

My pump is on the engine, power steering works fine. I ordered the deere service manual, its about 800 pages. Hope it has good info. Anyone ever close the hand valve under seat for cold weather warmup? Does power steering continue to work with this valve closed? I wonder if something is stuck on mine

I am currently going thru same problems with my recently purchased JD850 ('79, me thinks), no power steering. I have cleaned the screen, changed out the hyd fluid twice and it still gets lazy after just a little use. I'm fixing to change it out again. On mine, I get a noise in the case when clutch is released; I'm thinking here lately that its the hyd pump making the racket. It sorta chatters as it is trying to raise - and slowly, it does raise although not to the finished height.

I started a thread on the JD section several months back, I will find it and post it here although i have broadened the topic of the thread since I started it. I got the manuals and some info but kinda disappointed with them. Hyd pressure gauge is suggested to measure pressures and act from these numbers but I have not. Maybe next step for me before changing out fluid again and cleaning screen. Pump is $$$.

 

[lilburr]

Manual recommends hyd warm-up, I would imagine especially up where yer located. I'm not sure that it was real effective but I did warm up for several minutes. You got any unusual noise ?

 

[tbrown850]

No noises, just get normal noise with wheel turned all the way and can hear engine work a bit at idle.

 

[tbrown850]

Does anyone know how the hydraulic circuit works on this tractor? From what I can tell power steering is first and something isn't working right after that