Engine mount threads stripped

Subject is a 1995 Honda Accord LX V6.

I apparently removed the three “side engine mount” bolts, which thread into the “alternator bracket” without sufficient care. One is fine. Another hurt only the bolt thread. The longest one stripped the threads on the bracket.

  • A new alternator bracket is $150+.
  • There is no space behind for a nut on a longer bolt; the bracket back is not flat.
  • Perhaps I could grind the bolt head and put it in upside down with a nut.
  • Perhaps I could use a Helicoil kit. I’ve not used one before. It would change the thread from 1.25 to 1.5 or maybe 1.75. That’s about $30, I think.
  • Perhaps that’s all I can think of.

The question is: what would Jesus do, assuming that he had my meager budget, little time on his hands, and much greater experience and wisdom than I? No carpenter jokes, please (others welcome).

Bolts #14 (x2) and #16 on the left image, through trio of holes on part #5, into threaded trio of holes in part 2 on right image.

Junk yard?

Drill out the threads, and tap it for use with a larger bolt?

Room to go up one size on the bolt? If so, just drill the bracket and re-tap it. I wouldn’t want to do that on the engine, but it sounds like the threads are on the bracket itself so that shouldn’t be a big deal.

That’s a lot of work to do in a junk yard, I think. Think I might find somewhere it’s already removed for me?

That would require increasing the bore on both parts; a lot of trouble for a guy with just a cordless drill motor! These are 12x1.25; next size up is 14mm. It seems that the Helicoil option should be easier, I just don’t know whether the result is trustworthy.

What are we looking at: second drawing, the three localized holes lower mid-left, or other?

go next size up in sae not metric so its not a big jump silly. hit up the hardware store to find the proper bolt size.

Part #5 and bolts #14 (x2) and #16 on the left image (through holes) into threaded trio of holes in part 2 on right image.

Next SEA size is 1/2", already requires boring out the through-hole. Also, I doubt that 0.37mm size difference (radius) is enough to cut good threads. 17/32" is already 13.5mm.

Does anyone know whether a Helicoil kit, intended to fix spark plug holes, would be sufficient? Comparable to the strength of a #8 12mm bolt? That way I can keep the bolt size and through-hole, just re-tap the thread larger, use an insert, and change the thread pitch to 1.5 or 1.75.

i would helicoil it. it should be fine if installed correctly

helicoil is so you can use the same sized bolt. you still gotta drill it out to a certain size and tap that. if you have the bracket off take it to a shop and ask them to drill and tap it for a different bolt. its easy enough if you have a vise and a good tap and die set.

fill with jb weld drill and tap

will that really hold?

yah you never did it before? if u follow the instruction on the back it will work. i blew a hole in my 5hp briggs race motor and patched it with jb. never had a leak or anything, even patched my lifter valley with it, and i did a carb bolt hole