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806 weak hydraulics


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My 806 has 9800 hrs and I usually bale 800-1000 roll bales a yr with it and it has gotten to were it won’t hardly open the baler door unless it’s revved up. The hydraulic oil is 5 gallon over, filters been changed every yr, the rear remote pressure won’t go over 1200 psi, I flow rated it and it goes up to 1200 psi and flows right at 5 gpm and if I tighten it down to get the pressure up it drops off to 1-2 gpm. I took the top link cover off and on the draft control linkage there is hydraulic oil running down from somewhere up higher that I can’t see. Obviously it’s probably the  return to tank but I think it’s a bit much. Working the scv’s has no effect on how much oil is coming down which makes me think there’s a leak up there. What else could be leaking up there? I’ve took the relief valve out , seems to be working fine. Tried taking the unloader valve out and both holes on the snap ring broke so I have to dig it out now.  

P.S. I’ve searched and searched on here until I’m blue in the face but I can’t find my exact answer i I’m looking for. These tractors are getting older and I don’t know anyone local to ask about it, I work for a Deere dealer so this is kind of black sheep compared to what I usually work on.  Thanks! 

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Welcome to the forum!

The 1st thing that I would check is the relief valve that is located on the right side of the seat support.  It is the forward of two plugs that take an 1 1/8" socket.  You can swap it out with any relief from a 656 to a 1486 ( as long as the 86 series is not the pph closed center hydraulics).  There will be a difference in the psi ratings of the various relief valves, but this will tell you if the relief valve is the problem.  If this solved your problem, put in a new 2000 psi relief valve for the 806.  Note:  I have even installed 2300 psi relief valves in tractors like the 806 without problems.

If changing the relief didn't solve the problem, replace the o-ring on the unloading valve next.  A bad o-ring usually affects the 3-point 1st however.

If this didn't fix it, drain the oil and pull the rear hydraulic pump and check for a partially blown o-ring where the pump mounting flange contacts the rear end housing.  Note: When you reinstall the pump, you will have to install the short jumper tube from the filter side or else you will damage the suction tube seal.

If non of these ideas fix the problem, you will probably have to pull the large transmission cover.  There is a small valve on the 3-point linkage that is secured by 1/4" Allen-head screws.  They sometimes break and allow the oil to spill by.

Keep us informed as to what you find; we all learn from each other.

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Thanks for the info! I’m gonna pull the rock shaft the piston seals are leaking. The 3 pt hitch jumping every 4-5 Seconds with a 10 ft disc mower hanging off the back gets old after a while haha. While I have the rock shaft off is there anything o ring wise I need to change? 

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All the flow from that pump returns in the left rear corner. Deadhead an auxillary. If flow decreases oil is being lost at pump or mounting plate. If it sprays oil is getting past relief valve. If oil runs down from hitch valve. The action control valve is indicated. From your discription I suspect relief valve. There is an oring inside housing beside the one on the valve. 1200 psi at 5 gpm and no increase at 2 gpm along with standard relief being 1600 is whats telling me relief

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It’s not spraying out but it’s running out pretty good , more than I had expected for a wore out pump. 3 pt works fine btw it’s just the remotes that’s gotten slow. I noticed tonight I had the flow rater on trying different things  , when the oil is cold it won’t hardly flow anything at all until it runs for a couple minutes. 

881A9F36-AD97-4590-BB59-5160B3D40093.png

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14 hours ago, 64806 said:

Haven’t used the 3 pt since back in the spring but it’s been working fine , just slow at idle. Is the relief valve out of a 1486 the same just higher psi? 

Just set the valve to what you want I normally set at 3000 on my own stuff customers I set 2500-2800

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On 12/4/2019 at 11:19 PM, 64806 said:

It’s not spraying out but it’s running out pretty good , more than I had expected for a wore out pump. 3 pt works fine btw it’s just the remotes that’s gotten slow. I noticed tonight I had the flow rater on trying different things  , when the oil is cold it won’t hardly flow anything at all until it runs for a couple minutes. 

881A9F36-AD97-4590-BB59-5160B3D40093.png

tht is some nasty looking oil in there, looks like its got water in it - if thats the case i would also get the sludge out of the filter housing/filter while i was at it - if that thing is sitting outside its due to water - the only tractor i have that got like that was our  B john deere - it had enough water in it  from sitting outside it broke the oil pump shaft cause it was frozen stiff in teh cold, thats not fun to change either.

 

 

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2 minutes ago, cornerpost said:

Chances are everything will work fine with a good pump, filter, seals, and a 2000 lb relief valve.  Do not get carried away with too high a pressure.  And new fluid!

I’m gonna get a 15 or 17 gpm pump and change the pressure on relief valve,  o rings and the oil. And try that . 

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  • 1 month later...

Well I finally got cought up and got the tractor tore apart the rest of the way for now. I pulled the rock shaft housing to reseal the piston because oil was pushing right past the o rings. Anyways the tractor has had a god awful growl in the rearend for my entire life plus who knows how long before that. Once I got the rock shaft housing off I stuck a pry bar between the pinion and the housing and the pinion moves forward and back probably 1/16 an inch which explains were the growl has came from. The pinion and ring gear surprisingly look fairly good for a tractor with 10k hrs. How much trouble is it gonna be to tighten the pinion up? Split it at the rearend housing and then what all is involved? My next question is one of my hydraulic valves is wore out and doesn’t have hardly any detent to hold the lever and isn’t flowing oil right, the lever has to be in a certain spot for it to work. Is there parts still available for the valves or am I better off just buying a used one for it? And does anyone know where I can get the tall style hydraulic lever for the inside valve, mine has the early short square style. Thanks 

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On my 706 one of the bolts broke, one if three holding a valve on the side of the 3 point piston housing. That allowed a Teflon ring to blow out. The symptoms looked exactly like what you have. 

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I’ve got the rock shaft housing off , I looked last night trying to find were I can blow air into it to help push the piston out, as bad as it was leaking it should come out fairly easy haha

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Pics from a few days ago. 

Found the growl, pinion nut was loose and the gears on the bottom shaft have ALOT of wear and teeth missing, I’m guessing from the pinion shaft moving so much. 

C341EFDA-6D0D-4350-87C5-4ED00FDFCECD.jpeg

C29B0BDA-08D2-4571-AB7B-253EA86C03D0.jpeg

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Yea it’s been noisy for yrs but it’s gotten worse and started getting stuck in between gears this past yr. Don’t have any updated pics but got the wheels and fenders off and the axle pulled today. Ring and pinion will be here this week.

CIHTECH loaned me the pinion depth tool, I really appreciate it. I should be done with it by this coming weekend.  

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