Leaking/Stripped Petcock Mounting Bolt

[Prothec]

I have a leaking petcock mounting bolt on my XJ. The hole is stripped and I have a very slow leak at that bolt. I don't know how much metal is available for threads. The tank was extremely rusty with 25 year old gas in it when I got it.

Anyone have suggestions on how to take care of this?

[DAVINCI]

You could try running a tap in it to clean up whatever threads are left, then use teflon tape on the bolt. Get the yellow tape, it's fuel resistant. Worst case method, tap it for the next size bolt and do the same the the tape. Going up one size on the bolt may require enlarging the hole in the petcock, though. Just some thoughts.

[Prothec]

I never thought of using teflon tape. I need to bite the bullet and buy a tap and die set. I have three old bikes now, it isn't like I won't ever need it. The XJ also has a partially stripped hole on the oil pan that I was able to get away with a little longer bolt for now.

Is it actually threading into the edge of the tank or is there more material inside the tank that the bolt threads to?

It has been a while since I have emptied the tank to remove the petcock, but overnight it had leaked enough fuel that I could see it on the intake boot to the air box. It previously was only leaking enough that the bolt was a little wet, but no drips.

[BA80]

Yes, there is a strip of 1/8" steel in there that is threaded so going larger is an option but like Randy said you would need to open up the hole in the petcock also.

A thought I had when I read your post is to run a longer bolt down from the inside and use it as a stud and attach the petcock with a nut from the outside. It may be a little tedious getting the bolt in the hole from the inside but it would require fewer tools and no drilling and blasting. If you cut a slot in the end of the bolt with a hacksaw and use a screwdriver to thread it into whats left of the threads the only hard part would be getting it started.

JAT...

[crazy steve]

Buy a HeliCoil thread repair kit..... you'll wonder how you ever got along with it....

[Prothec]

A thought I had when I read your post is to run a longer bolt down from the inside and use it as a stud and attach the petcock with a nut from the outside. It may be a little tedious getting the bolt in the hole from the inside but it would require fewer tools and no drilling and blasting. If you cut a slot in the end of the bolt with a hacksaw and use a screwdriver to thread it into whats left of the threads the only hard part would be getting it started.
JAT...

That's thinking outside the box! If it were on the side with the fuel sender it could probably be done.

I need to learn how to use thread inserts. They sound interesting.

[DAVINCI]

The thread insert will STILL need some sort of seal against the original threads or it will also leak.

[BA80]

That's thinking outside the box! If it were on the side with the fuel sender it could probably be done.

I need to learn how to use thread inserts. They sound interesting.

I have used that method for repairing other problems like this and it worked quite well. Like I said, the hard part would be getting the bolt started from the inside. I went and looked at an XS tank when you posted and it can be done with patience and would be a permanent repair.

[crazy steve]

The thread insert will STILL need some sort of seal against the original threads or it will also leak.

That shouldn't be an issue here; the sealing is by the o-ring gasket between the tank and petcock, and the fiber gasket under the bolt head. With the OEM setup, fuel can get past the threads already. That's one reason going oversize may be a bit harder; you'll have to come up with a gasket to go under the larger bolt head....

[DAVINCI]

yeah, well, good luck

[Prothec]

The thread insert will STILL need some sort of seal against the original threads or it will also leak.

That's one thing I was thinking with a Helicoil. The other problem is if there is a limited thickness of the plate, I would imagine a Helicoil wouldn't work well. I would think a standard thread insert would be better where it's a solid piece with some magical adhesive on the outside, like the EZ-LOK kits.

[DGXSER]

Just watch the adhesive you use is fuel resistant/proof.

Other than the thicknes of the material, which is an issue for going a size over the same as it is for the helicoil, the helicoil would work just as Steve suggested. WHen you bolt the petcock to the tank, on the specials, there is that large O-ring which becomes oblong when inserted in the slot of the petcock. That is what forms the seal. The threads on the bolt just go up in the metal and it is no tighter a joint than the helicoil will provide. The bolt heads do get a fiber fuel resistant washer installed that seal it up.

[DAVINCI]

The teflon tape on the threads makes the fiber washer unnecessary.

[crazy steve]

The teflon tape on the threads makes the fiber washer unnecessary.

That may work on a standard petcock, but not on a 'special' unit like the XJ uses....

[cywelchjr]

That may work on a standard petcock, but not on a 'special' unit like the XJ uses....

Right, those just have an o-ring rather than the rubber gasket that captures and protects the screw area on the standards right? That would mean that the underside of the screw head on the specials where the washer is, is exposed to fuel all the time. Makes the standards system look better thought out all the time IMHO. Less hoses, less complex etc. The only thing the specials have going for them in that area is having an actual off setting, that and the teardrop tank for those who like the look (and it IS a good look, it's just too small).