Kubota Hydraulics O-Ring

[Fischer]

I've developed a leak under the seat of my L35 TLB. It's usually just an annoying drip but every know and then it's more than that with the "more" portion being intermittent. Like all leaks, it's getting worse and I need to get it fixed. The volume of fluid loss doesn't lead me to believe it's a blown hydraulic line but I could be wrong like a low pressure return line or something. I've been running the machine gently while trying to get all my necessary work done before I shut things down and begin the repair work. I've been checking the fluid level several times a day and actually the refill volume has been relatively mild. After doing some on-line research, I'm thinking it's likely a damaged o-ring in one of the solid hydraulic line connections under the seat. My tractor is a 2001 Glide Shift model. Over the years I've already replaced several of the hydraulic hoses on the loader and backhoe but I have not had to remove any of the solid lines and I'm a bit apprehensive.

I'm trying to gain as much insight as I can before I take the plunge and start removing the backhoe, access panels, etc. I'm not a mechanic but I've dome most of my own repair work over the years. I've got a fairly substantial supply of tools and skinned knuckles while doing it myself. With that said, I've also been in that unfortunate situation where I wished I hadn't started this repair "BUT" Im in too deep to give up.

If any of you have knowledge and/or experience in what I'm about to get into I'm all ears and would appreciate any advice. From what I've read on the net, this is not going to be pleasurable. Do any of you happen to know if Kubota uses just standard metric o rings or some special type like their hydraulic fluid. I don't live close to a Kubota Parts Dept. so I'd be interested in picking up any relatively inexpensive things, like o-rings, before I get started. I'm also thinking as long as I've got her torn down, replace whatever is reasonable while I'm in there.

Thanks for any information or advice you'd like to share. It's funny how we get so dependent on the near "every day" use of our equipment and wonder how we'll get things done while they're down for repairs.

 

[North Idaho Wolfman]

No needed to really disassemble it.
There really is only a couple places it can leak and pulling this cover they will be staring you in the face.

 

[Fischer]

Thanks for the reply Wolfman! Would you happen to know if the o rings are a Kubota OEM design and/or higher quality or just standard metric o-rings? I don't want to skimp on quality vs anticipated time to make the repairs. There's a lot of inferior and less expensive materials out there but if OEM is worth it. I have no problem with the higher cost.

 

[North Idaho Wolfman]

Thanks for the reply Wolfman! Would you happen to know if the o rings are a Kubota OEM design and/or higher quality or just standard metric o-rings? I don't want to skimp on quality vs anticipated time to make the repairs. There's a lot of inferior and less expensive materials out there but if OEM is worth it. I have no problem with the higher cost.

I personally always use OEM parts like O-rings, and I've not had one fail yet!
Are they better? not sure, but I do know Kubota uses some odd sizes and I know if I just order the right ones, they seal properly.

 

[Russell King]

And they are not very expensive from the dealer (at least not the ones I have purchased for my tractor)

 

[whitetiger]

Thanks for the reply Wolfman! Would you happen to know if the o rings are a Kubota OEM design and/or higher quality or just standard metric o-rings? I don't want to skimp on quality vs anticipated time to make the repairs. There's a lot of inferior and less expensive materials out there but if OEM is worth it. I have no problem with the higher cost.

If you do not want to possibly replacing an O-ring more than once, get the correct O-ring.
Been there, done that, got the Tee shirt, mug, wall plaque, and bumper stickers.

 

[Nicksacco]

@Fischer here are some pics of my L35 while going thru restoration.
I hope this helps you.
Without pulling off the seat and seat mount, and seat base, it'll be hard to see (not impossible).
You could remove just the seat and mount and front cover as Wolf suggested to start however and poke around. Seat mount is very heavy!
Removing the seat base requires disconnecting from the fenders, disconnecting the gear shift mechanism, removing the 3-Pt Hitch adjuster, hand throttle, and is just a bit more complicated.
If you've "been there" already with projects, then you can handle this! Take pictures.

Here are potential leak points.
Pipe #1 is delivery from the front pump
Pipe #2 is delivery to FEL controls
Inside the #1 and #2 round unit is a valve that decides Hyd oil flow for FEL or 3-Pt Hitch. If you take this apart - see the diagram below

Seat mount

If you need any more assistance let us know.
GoodLuck

 

[Fischer]

Thanks to all for the help, great forum and great information.

I haven't started removing panels yet. I have a question regarding removal of the three point adjustment knob and/or shaft that runs through the removable access panel below the seat. The knob has to be removed to remove the access panel. I thought the knob might just unscrew from the linkage shaft but that doesn't appear to be the case as it didn't seem to want to unscrew. I have a parts cut sheet that shows a pinch pin and what looks like a two piece adjustment arm with the adjustment knob on the outer portion. From the excellent photos Nicksacco sent, it appears the pinch pin and adjustment knob have been removed. Once the screws holding the access panel are removed does the panel slide forward, toward the adjustment knob, and expose the pinch pin for removal of the adjustment knob?

Thanks again for all the replies, I very much appreciate the effort and information you all have provided. I've been using the machine very lightly while trying to complete a project before starting the repair work. From what I'm seeing, it appears the leak is probably related to use of the loader bucket but I'm not sure. I just finished the project so I plan to beginning repairs in the next few days.

 

[North Idaho Wolfman]

In Nick's picture just the knob has been removed, that can be tricky, you heat it up and pull it off.
But you can pull the panel and remove the split pin (cotter pin) from the rear and pull it off that way without damaging the knob.

 

[Nicksacco]

Curious to see where your leak is coming from @Fischer.

CORRECTION: I misidentified the steel pipes above! Apologies.
Pipe #1 is delivery to FEL controls.

Pipe #2 in the picture above connects to another steel pipe that runs along the right side of the transmission case and up to the front pump. The joint is about where the Hyd filter is located.
Be careful if you take this joint apart. Mine was horribly rusted and I had to do some "shop engineering" to get it to work properly (hopefully your machine won't be messed up as mine was.

If you decide the leak is in the round portion where the two pipes meet, there are some support brackets that need to be removed so you can access that section. My advice is simply trace the pipes underneath the machine so you have a good idea of the layout before you start. In my situation, I'd already removed what was left of the floor and had access to everything.

 

[Fischer]

Thanks for the information.

The other day I started to remove the access panel to take a quick look and see if I could spot where the leak was coming from and maybe preorder parts before actually starting the repair. The very first thing I encountered was the question of how to remove the control knob. There is no locking nut on the back side of the knob to tighten/loosen and unscrew it. I thought if something that simple appears to be a problem, maybe I'm getting too old and this is going to be a real pain.
Next, I read on another site, removing and reattaching the hard lines is a real hair puller. One guy mention just flexing the hard line out of the way to replace the o-ring. However, another said I would have to remove the hard lines to access the o-rings and/or repair a ruptured line. I've always been hesitant to flex solid lines so I had presumed removal would be required. The guy went on to say removing the line is a real pain because of extremely tight access. That's when I started to reconsider doing the repair myself. I've done most of my own service and repairs on all my equipment over several years. Some design engineers take into consideration future repair requirements, others seem oblivious and make it nearly impossible without complete disassembly of half the machine.
With the information you've provided I plan on jumping into it myself and I very much appreciate your input. Ha, at least now I know how to remove the control knob!

 

[Nicksacco]

@Fischer I totally get it. A couple of thoughts:
As Wolf indicated above that that knob isn't a fancy thing - essentially you pull it off after a bit of heating. Or you can punch out the roll pin.
The plastic knob part number is T0070-34560 and is about $10 - But you could probably make one if you wanted to.

Before you get excited about removing a lot of components - I don't think you've identified the exact leak have you? Maybe I missed something. Anyway, if you remove the seat and seat mount - just a few bolts, it may look less daunting. If you want to remove the seat base, you can work bolts and things with the rear tires on, but it does make it more difficult to get to some bolts behind the rear tires.

You may want to degrease and pressure wash things, dry and run the tractor to really identify the leak source. You may not need to remove those two steel lines after all.

It does seem dumb to have to disassemble all that stuff just to see the top of the hydraulic cylinder and such, but it is a quick way to build a machine eh?

I tore my machine all the way down because of it's poor condition and decided if I did it that way, I wouldn't miss anything. Your machine is likely not that bad!

Anyway goodluck whtever you decide.

Sometimes it helps to see the real thing - here is the seat base after some work and primer.
Red are bolt holes that go into fenders and Blue are those that bolt into the floor.
The Differential Lock stays on the seat base and just needs the linkage disconnected.

 

[Fischer]

Well, I found the leak and it's right where Wolfman & Nicksacco suspected it would be. Fluid is coming out of the solid delivery pipe connections labeled "pipe #1&#2 in Nicksaccos' initial picture posting. Wolfman had that connection highlighted as a suspected location in his posting too.

I'm about to start degreasing and removing parts. I can't really tell if the fluid is coming from the o-rings in pipe #1 or #2 but I plan on replacing all four o-rings in both line connections while I'm there. I've removed the seat base, three point hitch control knob & access panel. I'm hoping I can disconnect both ends of both solid lines and wiggle the connections off the studs without having to remove more tin like the fenders, etc. We shall see but it doesn't look like there is enough room to clear the studs without removing more tin.

 

[Nicksacco]

Good deal @Fischer !
Thanks for getting back to us
You should be able to remove pipe 1 without any issue. It goes to a hose for FEL.
Pipe 2 goes to another steel pipe to the front pump. That joint can be a real pain. If you can avoid separation by removing brackets, then avoid it. Then again, mine was in bad shape and i had to do some "custom welding"

 

[Fischer]

And they are not very expensiv

 

[Fischer]

I installed the new o-rings & unfortunately it wasn't a fix. There is a pin hole in the weld area of the outer line, right where the pipe is attacked to the round fluid distribution fitting. The pin hole is right in the bottom where it's not easily visible. Nothing leaks until I raise the loader. I called Messick's (Kubota Dealer) for availability and price of a new line. After checking their sources, they said this line is very scarce but there may be just one available down in Texas. I told them I'd see if I could get it repaired locally but if needed, I'd get back with them on trying to locate a new replacement.

Question:
1) Should I even consider having it brazed and repaired locally or would that be just a short term, emergency type repair? Is it a situation like a rusting car, once a pin hole develops others will soon appear? I called a local hydraulic shop, they couldn't do the repair and they didn't seem too keen on having it repaired. It sounded like they felt a repair would suffice only as a quick emergency type fix. I'm checking with others.

The outside of the pipe and fitting appears in very good, almost new condition, other than the pin hole. In fact, the only place any paint is missing is the tiny pin hole area in the weld and some very minor surface rust on the bottom of the round distribution fitting. I wouldn't think an oil line would rust from the inside so I assume there was probably a slight imperfection in the original weld and it finally failed do to vibration or pressure.

The removal went relatively well but nothing I would like to repeat as a result of a "short term" emergency type repair. So with that in mind I'd appreciate any thoughts on the longevity of a "quality" weld repair vs replacement. The cost of a new part isn't a concern vs the thought of having to do this all over again. However locating a new part and awaiting delivery could be a problem.

Thanks again,
Fischer

 

[TheOldHokie]

I installed the new o-rings & unfortunately it wasn't a fix. There is a pin hole in the weld area of the outer line, right where the pipe is attacked to the round fluid distribution fitting. The pin hole is right in the bottom where it's not easily visible. Nothing leaks until I raise the loader. I called Messick's (Kubota Dealer) for availability and price of a new line. After checking their sources, they said this line is very scarce but there may be just one available down in Texas. I told them I'd see if I could get it repaired locally but if needed, I'd get back with them on trying to locate a new replacement.

Question:
1) Should I even consider having it brazed and repaired locally or would that be just a short term, emergency type repair? Is it a situation like a rusting car, once a pin hole develops others will soon appear? I called a local hydraulic shop, they couldn't do the repair and they didn't seem too keen on having it repaired. It sounded like they felt a repair would suffice only as a quick emergency type fix. I'm checking with others.

The outside of the pipe and fitting appears in very good, almost new condition, other than the pin hole. In fact, the only place any paint is missing is the tiny pin hole area in the weld and some very minor surface rust on the bottom of the round distribution fitting. I wouldn't think an oil line would rust from the inside so I assume there was probably a slight imperfection in the original weld and it finally failed do to vibration or pressure.

The removal went relatively well but nothing I would like to repeat as a result of a "short term" emergency type repair. So with that in mind I'd appreciate any thoughts on the longevity of a "quality" weld repair vs replacement. The cost of a new part isn't a concern vs the thought of having to do this all over again. However locating a new part and awaiting delivery could be a problem.

Thanks again,
Fischer

Unless its rusted out simple repair for a weld shop. Good asvif not better than new.

Dan

 

[North Idaho Wolfman]

Yep common practice to repair that fitting by welding it.
Either TIG with a good filler rod or Oxy with a silver rod.

 

[Nicksacco]

Glad to hear that's all it was!
As mentioned above a small weld will fix it.