Final Drive Housing leak -T190

mfiveash · Nov 13, 2021

Hello,

I found a pin hole leak from my final drive case housing on my Bobcat T190. It is leaking a remarkable amount from such a small hole. I removed the track and cleaned it up a little and when operating it starts pooling at the 9 o’clock side below the hydraulic lines.

Obviously, I would rather not replace the final drive motor at the excessive price. I think replacing the case housing would lead to a lot of precision work and probably more problems.

Is it possible and would you recommend for me to just spot weld over the pin hole leak? I would also change the drive oil and replace the case in line filters, but hoping I can just clean it up real good and bead a weld on it. Thoughts?

skata · Nov 13, 2021

It's hard to tell what I'm looking at in the pics. But if you say there's a pinhole leak in the casting, I'd say give it a shot with welding.

mfiveash · Nov 13, 2021

I know, kind of a bad picture and was before it was cleaned up. I put UV dye in the hydraulic fluid to find it. The second picture shows where it is pooling. I attached another picture of the unit with an arrow where it has a hole.

skata · Nov 13, 2021

You going to mig or tig weld it?

mfiveash · Nov 13, 2021

skata said:
You going to mig or tig weld it?

Glad you asked. I actually only have a Miller stick welder. Have never used a mig or tig welder, so guess it has to be stick. Is that okay?

skata · Nov 13, 2021

mfiveash said:
Glad you asked. I actually only have a Miller stick welder. Have never used a mig or tig welder, so guess it has to be stick. Is that okay?

Oof, I'm not sure about that. Hard to get a precise weld without over penetrating. If it's a pinhole leak, the metal there must not be that deep.
I'd also sand that area and visually double check that it's just a pinhole leak.

mfiveash · Nov 13, 2021

Oh boy. That is bad news. Maybe I will hire a guy to do it. Would you recommend mig or tig. I don’t know anything about either.

thanks for all your help!

mfiveash · Nov 13, 2021

I think I know a guy who can mig weld it. Going to have to get it very clean though and will cost more than I like, but if it works then it will be worth it.

skata · Nov 13, 2021

I think tig weld is what will work best, and provide the most control while welding.

willie59 · Nov 14, 2021

TIG is the best process for that, but the problem is going to be oil contaminating the weld area while attempting the weld repair. Not trying to dissuade from attempting the weld repair, only saying it may not work as hoped.

Tones · Nov 14, 2021

Have you checked the oil level in the planetary. If it's overfull then welding is counter-productive. The only cause for overfull hub is poor sealing between it and the hydraulic motor. In turn that can be caused by a worn motor which can be reconditioned. New hubs from the dealers can be a rip off

mfiveash · Nov 14, 2021

willie59 said:
TIG is the best process for that, but the problem is going to be oil contaminating the weld area while attempting the weld repair. Not trying to dissuade from attempting the weld repair, only saying it may not work as hoped.

That was a thought, but it seems it only oozes from that location when I start the bobcat and then comes out faster when I operate the final drive. I would hope it can be welded after getting in there good and sanding it down a bit. Really don’t want to try to recondition it…

mfiveash · Nov 14, 2021

Tones said:
Have you checked the oil level in the planetary. If it's overfull then welding is counter-productive. The only cause for overfull hub is poor sealing between it and the hydraulic motor. In turn that can be caused by a worn motor which can be reconditioned. New hubs from the dealers can be a rip off

Is the planetary the same as the Cam? Where the synthetic final drive oil goes? I do plan on draining and adding a couple ounces since tracks are off. If it is over full I guess that will be obvious since much more will come out than expected. Also, having absolutely no problems operating the bobcat, just noticed it was leaking after seeing the sight glass was low. Maybe I caught it early?

mfiveash · Nov 14, 2021

Went back and cleaned it up the best I could with it still connected to the machine. It’s very inconvenient as it’s out in the woods about 20 miles from my house.
Anyhow, so the small leak is coming from a rusted chipped off area at a plug. Didn’t see the plug with all the grime.

Not sure it would help replacing plug since the housing is chipped/rusted there. What are the thoughts of still welding it? I know the plug would not come off without grinding it, but no reason for that. Problem is I can’t get all the way around the plug so it would only be welded where the hole is. Will the leak still find a way out since I doubt the o-ring would survive the heat?

Tones · Nov 14, 2021

While I'm not familiar with your machine and only writing in general terms and having rebuilt a few drive hubs and motors. The plug you found could be the drain for the gearbox and welding it could make very difficult to be removed in the future. Checking the oil level of the gearbox will determine what the real problem is. Overfilled planetary gearbox can generate high pressure and will force oil out of the weakest point. I've had a shaft seal blow in towards the hydraulic motor, another blew out the Duo Cone seal and another blew out the seal on the faceplate. If the oil level is good then removing and replacing the plug would be a better fix.
Depending on how bad the leak is checking the oil level should become part of your prestart checks until the repair is done.

skata · Nov 14, 2021

I know everything is probably rusted, but can you remove the lines and take the drive off?

mfiveash · Nov 14, 2021

Will be checking the oil level next weekend. Was just making a plan so I have the welder scheduled. Not thinking that is a great idea now. Ugh. Back to square one. Yea, I can try to take off the lines, but they are so rusted it is likely will need to replace all the 90 degree connections.

What if I just JB weld that spot? No heat and it isn’t the drain plug. It does have a spring and a spool behind the plug, but can’t get it off anyhow so might as well keep it closed up. Is JB weld any good? Will it last?

or just take it off and replace everything necessary. Ugh

skata · Nov 14, 2021

I don't know buddy. I feel for you though.

Tones · Nov 14, 2021

Im guessing that under the head of the plug there is an 0 ring seeing as it's part of a spool assembly. Could be getting easier and cheaper to fix all the time.

mfiveash · Nov 16, 2021

Okay, ordered a $72 plug with $25 shipping. Now I have to see if I can remove this old one without causing more damage and hope the new plug doesn’t still leak. I will keep y’all updated. Thanks for all the help.

Final Drive Housing leak -T190

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