Flapper box thread size

[74TT]

Trying to come up with a better way to attach my new flappers to my car.
When taking off the nuts, they of course all snapped off, leaving a smaller
stud behind. My thoughts are to make a threaded sleeve to screw on the
broken studs (which may cause me to enlarge the holes in the flapper) and attach the boxes with a new bolt.
If I can determine what size the old studs are, I can probably make something work. I'd like to figure this out rather than weld them on.

Thanks for any and all input.
Cheers!
Steve

[Cooper911SC]

Most likely M6 1.0 thread pitch.

Extending the studs will be a challenge as it will also likely require a spacer on the outside as well. This would be needed to allow the new nut to put clamping force against the outside of the flapper box.

Honestly easier to find a local shop and have them TIG weld some new studs in.
OR a muffler shop might be easier and cheaper. MIG will leave a tiny bit more splatter.

Cooper

[74TT]

Thanks Cooper! I appreciate it! I may be going that route, mig or tig that is,
but I'd like to leave that for a last resort. A friend also suggested drilling the
old studs out and using large sheet metal or self tapping screws.
We'll see.
Thanks again,
Steve

[irobertson]

I broke all three off on one side of my car. I drilled and tapped the holes, then put the flapper box on with M6 bolts instead. Not as easy as putting nuts on studs, but I got them in there.