transmission mount bolt threads

[inaminit]

Hello-On Sunday I took the engine out of my 76. Next will be to clean up some hack wiring in the engine bay and get it ready for the 3.2 install. When I removed the transmission bolts-both turned out to be non-standard slightly longer versions without the pointed tip. One has coarse thread, the other the original fine thread. When I screwed the bolts back in-they fit loosely and it feels like there are not many threads left in either socket. So-what to do?
1. I could clean the sockets and use a generous amount of loctite at reinstallation.
2. Drill out the threads and tap a larger thread size. How much metal depth is available in the socket?
3. Another method?
Thanks in advance for your answers.

[schumicat]

I have seen people report helicoil and similar inserts work well here. it sounds like someone already may have tried that given the different threads. I wouldn't try #1. loctite keeps a bolt from backing out due to vibration, etc., but I don't think it will do much if the bolt fits loosely in the first place.

[Iciclehead]

I stripped one a while back, learned the hard way to loosen the mounts on the transmission mount, get the bolt started and then tighten everything up.

I helicoiled the hole, it was a PITA but there have been no problems to date (2 years).

Dennis

[inaminit]

If you were going to use a helicoil-dosen't that require drilling out a larger hole and screwing in the coil? If so wouldn't it be better just to tap a larger thread?

[yelcab1]

Originally Posted by inaminit

If you were going to use a helicoil-dosen't that require drilling out a larger hole and screwing in the coil? If so wouldn't it be better just to tap a larger thread?

you end up with a larger hole, but a helicoil reduces the size to the previous hole size. This is so you can continue using the stock bolt, with the self centering tip. If you do not mind a larger bolt, then you can tap a larger thread size hole.

[dshepp806]

Time-Sert!

Doyle

[Porboynz]

Time cert or heli coil, all good, common issue. Once repaired make sure you have original bolts and ensure they do not bottom out. If you use non original fasteners adjust with slightly thicker washer or shorten non original bolts but make sure they do not bottom out because that will destroy the thread.

[inaminit]

Time sert or helicoil it is then. Does anyone have a loose trans bolt that they could confirm that the thread is M12x1.5? thanks again.

[70SC]

you are correct sir M12 x1.5