Leaking from bolts on rear diff

[BostonJon]

Hey everyone - need your collective wisdom here.

I had a leaking third member and replaced the old paper gasket with a new LubeLocker gasket. I thought all was well but now I am getting seepage through the bolt holes. My previous leak was at the mating surface between the third member and diff housing but this is now clearly coming from the lower bolt holes (those below the fluid level). It seems to me like the LubeLocker gasket is not sealing well around the bolts. I really thought these gaskets were supposed to be superior and I’m dreading the possibility of doing this job again. I’ve tried to tighten down the bolts a little more than the torque spec but it hasn’t helped.

Any thoughts/ideas?

 

[mtbtim]

Do the job again and use Toyota FIPG 1281. In my opinion, FIPG is superior to a paper gasket because it can flow into any imperfections in the steel mating surfaces. If the mating surfaces are perfect, a paper gasket will suffice. Whenever it's a choice between a paper gasket or using FIPG, I choose FIPG because I'd rather just do a job once. it takes more time to apply FIPG, but it's worth it if it means you're not going to be in the situation you're currently in with either living with your 3rd member leaking gear oil or going back in and doing the whole job over again.


Toyota FIPG 1281 - (For Transmissions, Transfer Cases and Differentials)
https://amzn.to/33w0yma

 

[BostonJon]

Thanks, Tim. and thanks for your video on swapping the third member - that’s what I used for this job and it was tremendously helpful.

I replaced the mounting studs with bolts while I was doing the job but I don’t think that would have caused the leak. Like you mentioned - perhaps the mating surfaces are not perfectly flat. That’s actually why I avoided the paper gasket and used the LubeLocker - I figured it had some more width and would make a better seal. I guess not.

I ordered 00295-00103 this morning. Is that not the right stuff?

 

[theesotericone]

I replaced the mounting studs with bolts while I was doing the job but I don’t think that would have caused the leak.

Did you loctite the new bolts into the housing when you replaced them? They need it to not leak past the threads.

 

[mtbtim]

I replaced the mounting studs with bolts while I was doing the job but I don’t think that would have caused the leak./QUOTE]

Did you loctite the new bolts into the housing when you replaced them? They need it to not leak past the threads.

Yeah, this is a different story since the OP removed the studs and replaced them with bolts. OP, did you notice that the factory stud threads had signs of thread locker on them? If they did, this would explain your leak through the bolts.

 

[mtbtim]

Thanks, Tim. and thanks for your video on swapping the third member - that’s what I used for this job and it was tremendously helpful.

I replaced the mounting studs with bolts while I was doing the job but I don’t think that would have caused the leak. Like you mentioned - perhaps the mating surfaces are not perfectly flat. That’s actually why I avoided the paper gasket and used the LubeLocker - I figured it had some more width and would make a better seal. I guess not.

I ordered 00295-00103 this morning. Is that not the right stuff?

You got the wrong FIPG. The one you got is for engine applications and it's black in color. The FIPG for transmissions, transfer cases and differentials is red.

 

[BostonJon]

Thanks everyone.

I just ordered the red FIPG and cancelled the black.

And yes, the old studs did have some sort of thread sealant on them. I figured since the new gasket had rings around the bolt holes that this wouldn’t be an issue. Would Thread sealant work to prevent leaks? I always thought that was just to keep the bolts from backing out.

 

[mtbtim]

Thanks everyone.

I just ordered the red FIPG and cancelled the black.

And yes, the old studs did have some sort of thread sealant on them. I figured since the new gasket had rings around the bolt holes that this wouldn’t be an issue. Would Thread sealant work to prevent leaks? I always thought that was just to keep the bolts from backing out.

The loctite is mainly to assist bolts from backing out, but in this case it could also prevent gear oil from coming through as well. Blue 242 isn't a super strong bond and that's what I would use. Don't use the red thread locker because then you'll have a hell of a time getting the bolts back out. You'd want to drain your rear diff, spray some break cleaner into the threads to get them clean and the re-insert the bolts with a blue 242 loctite on them.