b7100 3 pt bleed down

[Lil Foot]

Glad you got it fixed, & thanks for reporting your results!

In my case the piston wouldn´t come out just by lifting the arms. the rod inside the piston didn´t push far enough.

If memory serves, I think mine was the same way, hence the magnet.

 

[4rider]

Lil Foot,
I have a hydraulic leak from the cover plate on the hydraulic cylinder, under the seat on my Kubota B7100D gear drive tractor. Found and followed the suggestions in the forum and replaced the o-ring on the piston and the other one on the cylinder cover. However the hydraulic leak is still present. Leak coming from the cover plate. Apparently just replacing the o-rings won't fix the leak.
Parts manual calls for ring (part #67211-36420) on the piston, which I didn't have present when I dissembled mine.
Does anyone have clue why the leak persists even after the two o-rings are replaced?
What is that ring, the parts manual calls for?
Thanks,

 

[Lil Foot]

OK, there is an o-ring on the piston (#60) , and the extra ring (#61) is a backup ring, which supports the o-ring. (keeps it from moving back & forth & rolling over)
Then there is the o-ring that seals the cover, (#63) and another o-ring (#62) that seals the small port that feeds oil under pressure to the top of the piston. (or the auxillary port on the diverter valve, if its switched that way)

Have you got all of those in place? Mine did not have the backup ring when I got it, and also had a bunch of red silicone seal slathered all over under the cover, but I cleaned it up & it seals completely with just those o-rings now.

I had a hell of a time keeping that #62 o-ring in place while I replaced the cover, so I ended up tacking it in place with a tiny spot of crazy glue- worked great!

 

[Lil Foot]

My backup ring looked like this:

 

[4rider]

Lil Foot,

thanks for the quick reply. Your diagram looks nice a clean.I use the illustrated part list from Kubota's main page.

When I bought my B7100 gear drive it had the signs of minor hydraulic leak from the control valve, although the tractor was so filthy, that it was impossible to tell where the leak is from.
After extensive use of the 3 point hitch it developed a leak from the control valve cover (oil pressure group 2). I've searched and found your posting of how to correct the issue (i.e. replacing the piston and cover o-rings). Nice write up with pictures that come very handy! Got to get this magnet too!

Mine did not have the backup ring, and the o-rings didn't look completely toasted, so I'm guessing the previous owner did replace the o-rings, but did not put the backup ring back, thus the area leaked a little bit.
I've placed order for the backup ring (thanks for the picture), but had a hard time to locate the correct part number for #62 o-ring. Ordered one with part #04811-00080, but wasn't the right size.It was smaller. Do you have the part number for #62 o-ring?

 

[Lil Foot]

but had a hard time to locate the correct part number for #62 o-ring. Ordered one with part #04811-00080, but wasn't the right size.It was smaller.

Now that you mention it, I remember the one they gave me was the wrong size also..... part change over the years? Anyway, I picked one from my o-ring assortment and it worked fine, but I have no idea what size it was, sorry. If I remember right, there is a small recess that it sits in, so I just picked one that fit the recess & was a hair thicker than the old, squashed one. In hindsight, I guess I should have written down the size, for future reference.

 

[4rider]

Thanks for the tip. I'll stop by Tractor Supply on the way home to pick up some o-rings to replace #62. I'll use a drop of glue to keep in place as I lost it once when was putting the cover back.

 

[Piker]

With your lift arms disconnected from the lower 3 point arms you can snap them up quickly & usually forces the piston out far enough to get hold of it to pull it out. My hitch on my 1980 B7100 frifts slowly down with an implement attached but not in use. Replaced O ring & backup washer & lightly honed the cyl. - no change. Gonna live with it, just can't brag about it over a beer! Have it split right now over a clutch issue, will post seperately when parts arrive & I get it back together - will be a bit wordy but might prove helpful to othere 6000/7000 series owners.

 

[4rider]

After replacing the o-rings on the piston and fitting back ring too it looks like the 3PH leak is addressed
I also used the time to replace the transmission/hydraulic fluid using Kubota Super UDT2 and clean the transmission screen filter. It's probably me, but I have the feeling the gears are shifting better and hydraulics are working better and faster.
Thanks Lil Foot on all info with fixing this pesky leak.

 

[Lil Foot]

4rider- No problem, & thanks for reporting your results!

 

[trinityBE]

Hi,

Sorry for bumping this old thread, but i have some questions about the backup O ring.

I was replacing the O-ring on the piston [60] for obvious reasons till I found this thread. Apparently there is also a backup O-ring [61]? Is this the same size O-ring as [60]? And where do I put it ? (on/in front of the piston?) because mine did not had any when i opened it up

Thank you for you inside guy's

 

[Lil Foot]

The backup ring is not an o-ring, but a (usually) plastic support ring.
The one for that 3 pt piston is a spiral cut PTFE like the one pictured below.
You sort of thread it into place.

 

[Lil Foot]

And it goes on the piston, in the same groove as the o-ring, o-ring nearer the crown, backup ring nearer the skirt. Mine did not have the back up ring, either.

 

[hub]

Can anyone tell me where the o-ring & backup ring on the lift piston is on my B7100

I had not seen Lil Foot diagram, I think I know now, sorry for the post.