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I have a 855 john Deere with the battery in the front and fuel tank behind the dash. I cant figure out why the steering has no power. I have checked the steering valve, PRV valve and it it getting oil but just hard to turn. It turns good with a counter weight on the rear but that's because it takes the weight off the front. Does anyone have any advice? Oil levels are good, rockshaft and 3pt work good, transmission is sound. just no power steering and i believe my loader is also slow so it come back to the PRV valve. But i checked all the valves in the loader valve coup and no blockage.
 

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You cleaned the screen for hydraulics?

Possible the seals in steering cyl are leaking internally.

Do you have a copy of repair manual??..if not I can post a link here in a bit
 

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You cleaned the screen for hydraulics?

Possible the seals in steering cyl are leaking internally.

Do you have a copy of repair manual??..if not I can post a link here in a bit
I have all the books. The screen is good in the rear. Well that was one thought but I got to try my loader. If the loader is fast my cylinder may be the issue but if it's slow then it goes back to pressure I'm thinking. I just don't have a pleasure Guage at the moment to check the valves.
 

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If you're having problems with the power steering and loader speed the common denominator is hydraulic pressure and / or volume. I'd suggest you test the pressure first. If you don't have that capability then drain your hydraulic fluid and check the suction screen and secondary filter if equipped.

I had a 950 back in the 90's and don't believe it had a secondary hydraulic filter.
 

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i just got a preasure guage on the loader outlets and it was abbout 200 psi. on the rear pump all the way revved up i was reading 500 psi. Does that sound right ?? or should it be in the thousands?
That's waaaaay low. You said you had the books, the specs should be in there.
 

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i just got a pressure gauge on the loader outlets and it was about 200 psi. on the rear pump all the way revved up i was reading 500 psi. Does that sound right ?? or should it be in the thousands?
Your hydraulic pump pressure relief valve may be stuck open. Possibly some sludge or other debris, otherwise it could be a bad hydraulic pump but I tend to doubt it. Maybe a bad or slipping pump coupling.....? I'd remove the hydraulic pump and inspect it.

You may also want to disassemble and inspect the power steering flow divider pressure relief valve. Maybe the adjustment loosened and backed off.

Lastly, depending upon which SCV you have you may have a pressure control issue. Some have spring loaded pressure control valves.

850-950-1050 PS Pressure relief valve
 
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Any extra/added hydraulics?
 

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Alright, I got the old hydraulic pump on and got 3k psi. Looks good and now have 3k or so out of my loader valves. Still no power steering. I will count that as a win today and check my powersteering valve tomorrow. Im not sire why my new pump didnt work but i will also check my prv's tomorrow!
 

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You could remove the power lines and check to make sure they're not collapsed and restricted.

You can take the power steering control valve apart and inspect it. It's installed in place of the drag link. Old school power steering assist.

PS Control Valve

Also, some good news. The steering assist cylinder is repairable.

PS cylinder

The above information is based upon your 850 S/N being greater than 16001. If your S/N precedes 16001 then here's the link for additional information.

850 up to S/N 16000
 
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I think its an 855 He's got.
They don't have that part you showed as/drag link.
There is no steering box . Its all lines on a 955 which is what His late model 855 is based off .
Just a wheel to wheel tie rod and a hydro cyl mounted to front axle.
 

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I think its an 855 He's got.
They don't have that part you showed as/drag link.
There is no steering box . Its all lines on a 955 which is what His late model 855 is based off .
Just a wheel to wheel tie rod and a hydro cyl mounted to front axle.
Good eye Duke. I was coming back to the thread after a few days and was positive it was an 850. Will have to dig back in and provide some updated information.
 
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IIRC
The 850 1050 and probly several others of the "gear" drive were the Yanmar built...jd badged.
They do have a steering box and some had/have gealer added PS like what you show in place of drag link
Neighbors 1050 is built that way...why it has PS and No loader we can't figure out.
 

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After using a gauge on the power steering lines and hydraulic lines. I ended up ordering a steering valve assembly from a guy parting out a 855 in Wisconsin. I installed it and the POWER STEERING WORKS!! I took the old one apart and couldn't see anything wrong with it. The used part costed me $245. which isnt bad considering 1200 used on ebay and 2200 new from john deere. Thanks for the help guys. Doing this project helped me learn how to disassemble a 855 and reassemble it!
 

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Hang on the the old steering gear. They can be easily resealed and the kits are still available.


Sent from my iPhone using Tapatalk Pro
 
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