before I cut... trans carrier bolt sheared and spinning - any ideas?

Hello all. I have been posting my findings on 912BBS and thought I would ask here as well before the cutoff wheel comes out.

My car came to me with one trans carrier bolt sheared flush with the bottom of its hole on the trailing arm mount (1st pic). I cut a slot in the bolt and found it to spin easily but with no thread engagement - it will neither move in nor out. I welded a washer to it (2nd pic) and pried, pulled/turned to try and engage possibly damaged threads and no movement.

The 3rd and 4th pic show my understanding of this blind female thread with the hopes that anyone who has addressed this before or made repairs has a suggestion.

Thanks
Rus

912BBS thread: http://www.912bbs.org/vb/showthread....d-and-spinning

I subscribed .....

Looks like from your last picture that you got the bolt out. I've used a heli-coil to repair the threads.

Wow, you brought us a tough one. My thought is to remove your washer and use one small spot of weld at the bolt edge to prevent the bolt from spinning. Drill it out and, and as Ed says heli-coil.
Rob

Yup its a toughie indeed. My last post on 912 shows some more that I learned. I had drilled the "inspection holes" with intent of welding or holding the bolt to the tube to let me drill it, but it now seems so close to being able to be removed. But no luck. I tried prying heavily on the top of the bolt while using the impact on the bottom but could not get it to engage the threads.

I suppose drilling may be next.

From your description of the fact that it turns freely, but will not move in or out...

Either you can't get enough traction on the fragment to engage the threads or the threaded insert itself has broken with the wide flanged part that shows still attached to the trailing arm box.

When you look inside the box can you see an intact tube? Is it or part of it turning when you turn the bolt?

Not sure how you could drill out the remaining bolt if it turns freely...it will just turn with the drill bit.

If it's too free to drill...you might have to drill horizontally in the box and through the insert to pin the bolt in the insert..then drill the pinned bolt fragment.

Then it's helicoil, thread-sert, or a completely new insert welded in. Yikes!

Overthinking this. 30westrob and Ed nailed it.

Tack weld so the bolt doesn't spin and start drilling. Fortunately because the bolt is loose once you get near the bolt shank diameter you should be able grind your tack weld, collapse what's left of the wall of the bolt with a pick or punch, and you're home free. Count on final drilling, tapping, and installing a Heli-Coil. 1-2 hour job, tops.
Routine for us and makes for a very solid repair.

Quote:

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Originally Posted by Frank Beck

Overthinking this. 30westrob and Ed nailed it.

Tack weld so the bolt doesn't spin and start drilling. Fortunately because the bolt is loose once you get near the bolt shank diameter you should be able grind your tack weld, collapse what's left of the wall of the bolt with a pick or punch, and you're home free. Count on final drilling, tapping, and installing a Heli-Coil. 1-2 hour job, tops.
Routine for us and makes for a very solid repair.

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Perfect! And simple...the voice of experience.

I'm allergic to torches, but sometimes you gotta!