Kubota B5100DT 3 point hitch falling

[BonnySlope]

I'm aware this has been covered but not able to locate for my case....tractor
Well I got a new tool for my little orange work hand (B5100DT) I attached the box scraper to the tractor and did my 3 pt. linkage adjust raised RPM's to just under max (3000 just under full) and lifted without issues but immediately began to lower. Didn't see any leaks in trans/hyd. lines. I decided to check this I took for granted like interlock rod lockers. Made sure locker B was up against factory stop on rod (drivers end)and then measured out to the A locker end and had to adjust in to the suggested 4.88 setting ended up narrowing about .31. Second attempt it lowered a little slower but still had to keep an eye on with continued lifting. Before when I checked the interlock rod I slid a go/no go shim to the implement lowering speed nut and it was fine. New territory here for me is I believe I read that closing nut completely and if lift held when closed would indicate your piston O ring was fine. What I'm going to do is work in quarter turns... Ok I will try closing it to see if it will hold.
Wouldn't mine taking a look at the piston and cylinder wall and replace the O rings or ring. With the drawing I see they really don't show a good stacking order they show two, is one a whipper with the Back up Ring in the piston groove? and the other a closure O ring. using Messicks and I&T and Kubota Service manual.

 

[GeoHorn]

Not having that model tractor I’m not familiar with what you are describing as “locker A” or “B”, but....
When you say it is immediately lowering.... the tractor STILL IS RUNNING.... right?
The 3-pt will drift down at a speed commensurate with the condition of the cylinder and the let-down-knob under the seat when the tractor shuts down

 

[Chesapeake]

My b6100 had that issue of the 3pt slowly lowering. Oil leaking past the piston o-ring.
Old set up was an O-ring. Mine was very worn.
New setup was a thin spiral ring of white PTFE or UHMW and then the O-ring. Not sure if the plastic ring is a whisper, or just to take up space and make the O-ring fit better.
After replacement mine will hold my tiller up for hours now. Before it wouldn’t hold it up for 5 minutes.

Pretty easy change out. Just look for tutorials for B7100 if you can’t find one for a 5100. Should be very similar.

 

[North Idaho Wolfman]

Not having that model tractor I’m not familiar with what you are describing as “locker A” or “B”, but....
When you say it is immediately lowering.... the tractor STILL IS RUNNING.... right?
The 3-pt will drift down at a speed commensurate with the condition of the cylinder and the let-down-knob under the seat when the tractor shuts down

That model does not have a "let-down-knob" ( Drop speed adjustment ) under the seat.
It has a drop speed bolt on top of the controller.

 

[North Idaho Wolfman]

My b6100 had that issue of the 3pt slowly lowering. Oil leaking past the piston o-ring.
Old set up was an O-ring. Mine was very worn.
New setup was a thin spiral ring of white PTFE or UHMW and then the O-ring. Not sure if the plastic ring is a whisper, or just to take up space and make the O-ring fit better.
After replacement mine will hold my tiller up for hours now. Before it wouldn’t hold it up for 5 minutes.

Pretty easy change out. Just look for tutorials for B7100 if you can’t find one for a 5100. Should be very similar.

The white ring is back up ring.
It's job is to allow the O-ring to slide when hydraulic pressure is released.

 

[North Idaho Wolfman]

I'm aware this has been covered but not able to locate for my case....tractor
Well I got a new tool for my little orange work hand (B5100DT) I attached the box scraper to the tractor and did my 3 pt. linkage adjust raised RPM's to just under max (3000 just under full) and lifted without issues but immediately began to lower. Didn't see any leaks in trans/hyd. lines. I decided to check this I took for granted like interlock rod lockers. Made sure locker B was up against factory stop on rod (drivers end)and then measured out to the A locker end and had to adjust in to the suggested 4.88 setting ended up narrowing about .31. Second attempt it lowered a little slower but still had to keep an eye on with continued lifting. Before when I checked the interlock rod I slid a go/no go shim to the implement lowering speed nut and it was fine. New territory here for me is I believe I read that closing nut completely and if lift held when closed would indicate your piston O ring was fine. What I'm going to do is work in quarter turns... Ok I will try closing it to see if it will hold.
Wouldn't mine taking a look at the piston and cylinder wall and replace the O rings or ring. With the drawing I see they really don't show a good stacking order they show two, is one a whipper with the Back up Ring in the piston groove? and the other a closure O ring. using Messicks and I&T and Kubota Service manual.

Does the control for the three point snap back to center when it reaches max height?
Does the control snap back to center when it reaches max lowering?
Will the three point without any weight on it stay up at any height?

 

[BonnySlope]

My b6100 had that issue of the 3pt slowly lowering. Oil leaking past the piston o-ring.
Old set up was an O-ring. Mine was very worn.
New setup was a thin spiral ring of white PTFE or UHMW and then the O-ring. Not sure if the plastic ring is a whisper, or just to take up space and make the O-ring fit better.
After replacement mine will hold my tiller up for hours now. Before it wouldn’t hold it up for 5 minutes.

Pretty easy change out. Just look for tutorials for B7100 if you can’t find one for a 5100. Should be very similar.

Thanks Chesapeake, I did find a pictorial of some ones O ring replacement on a B7100. They just replaced piston O ring no wiper ring(UHMW or Poly) backing up O ring or cover O ring. I saw on Messick's they don't even list a cover O ring. On my tractor my covers not leaking. Other materials could be used to seal metal to metal surfaces.
Thanks again for finger point. Let me get on the phone and see if I can find local.

 

[BonnySlope]

Does the control for the three point snap back to center when it reaches max height?
Does the control snap back to center when it reaches max lowering?
Will the three point without any weight on it stay up at any height?

Hey NI Wolfman (no offence to shorten name) Thanks for input.
Does the control for the three point snap back to center when it reaches max height? yes
Does the control snap back to center when it reaches max lowering? yes
Will the three point without any weight on it stay up at any height? yes it does! Ok a very slow by pass but I have my safety chain on.
The spring has been spray lubed. I'll go through your questions again and monitor. My current response is what I recall... yes need to refresh what I recall.

 

[North Idaho Wolfman]

No offence taken, NIW is what most use.
Or some other things I can't repeat!

With what you said is happening pull the front cover and look fort pitting in the sleeve, if it's not pitted get a new O-ring and back up ring and You should be able to fix it.
If it is pitted or scored badly get a sleeve and maybe even a new piston.
Get a gasket or O-ring for the cover too.

 

[BonnySlope]

No offence taken, NIW is what most use.
Or some other things I can't repeat!

With what you said is happening pull the front cover and look fort pitting in the sleeve, if it's not pitted get a new O-ring and back up ring and You should be able to fix it.
If it is pitted or scored badly get a sleeve and maybe even a new piston.
Get a gasket or O-ring for the cover too.

Well I found O ring and backup ring(wiper) 11 miles (local) normally stocked, Back up due in on Thur. Have to make decision to prep now and use tractor to haul trailer and wait for tare down the day before. If we all could have such tuff choices this past year.
Cheers, thanks again will post revel.

 

[torch]

No offence taken, NIW is what most use.
Or some other things I can't repeat!

You can, but you'd have to ban yourself for a week.

 

[Chesapeake]

The cover/cap o-ring looks to be 04810-50550.
You’ll also want the little O-ring for the valve port 04811-00100.

 

[BonnySlope]

The cover/cap o-ring looks to be 04810-50550.
You’ll also want the little O-ring for the valve port 04811-00100.

Thanks for the numbers Chesapeake. I was lucky local dealer/supplier (11miles) has everything on shelf except Backer ring which will be in on Friday. I have enough property task to keep me busy until then

 

[BonnySlope]

Well I got it done and test lifts box scraper just fine. It's tight with nothing on 3 point I have to assist to lower arms.? May need a little adjust?
Bore measured 2.379 (factory is 2.36 with plus and minus) and the old O'ring was cone shaped. It would be interesting to see a new piston, it's like they only machine the O'ring grove and very light else where.
Need to put my weighted ag tires back on rear. My turf tires a slow leak in one and even with a tube they need to come off.
Chesapeak the value o'ring you suggest(parts C) and I checked Messicks and got a updated number it was only 88 cent but I was still trying not to have extra parts. I was able to match up from my O'ring inventory HF assorted box. Over all thirteen dollar and change for the fix. cool.
Thanks again folk for you thought.

 

[Chesapeake]

Good to hear.
Mine also needs assistance to lower the arms when there is no weight. I kind of expect that to go away after the o-ring takes a set and has some wear. It’s no issue to push them down though.

 

[BonnySlope]

Here a picture of the piston with new o'ring and

backer ring. Piston looks scared up but wiped down with 200 G wet and dry paper. See how old o'ring is coned