Drain plug stripped

So I recently got a 1978 JCPenney Pinto with an E 50. First time I went to change the fluid. I unscrew the bolt and it has a bunch of threads on it. Try to screw it back in and it never tightened up. help. Can I retap this? And if so what size do you suggest

Re: Drain plug stripped

Yea you can tap it, I bought a case once with a drain plug bigger then stock. I would tap it to the next size up if you can. Probably m10 & make sure the bolt is not to long because it will destroy the transmission

Probably don't even need to pre drill because the metal is so soft.

Re: Drain plug stripped

You could probably just screw in the the next size up bolt without drilling/tapping as mentioned, but might not go in and out very many more times without stripping threads. Best to take this opportunity to rebuild that e50 and get everything inspected/set up nicely. (edited)

Re: Drain plug stripped

they are usually a regular-ass thread pitch, measure it and buy a helicoil. fix it the right way.

Re: Drain plug stripped

I shoved a larger bolt in mine and used epoxy to keep it in. Prevents me from swapping out transmission fluid without feeling obligated to inspect the internals since the cover is already off.

Re: Drain plug stripped

Brad William /

Not sure if I recommend this. I had all the parts within reach at the time so it was a natural. 1/4 npt tap. 1/4 x 1/8 npt brass reducer bushing. 1/8 npt plug.

Tapped bushing into hole and tightened with red Loctite. 1/8 plug is plenty big to drain the tiny amount of fluid when needed.

Helicoil is the proper way to do this. For me the brass fittings were a simpler option.

Re: Drain plug stripped

I wonder if you could just use an expansion plug from the hardware store lol

Re: Drain plug stripped

Years ago my plug stripped on an MO2 engine. Auto-Zone had an oversize plug that fit perfectly on 8mm,I believe. Still you need to remove the aluminum bits inside the case so they don't tear up anything.

Re: Drain plug stripped

All the metal shavings going into the case. Best to split the case rather then wiping out the bearings. In the long run it might cost less.

Re: Drain plug stripped

Was it the main drain bolt or the bolt below the crank. I’ve sheared two of those in my time

Re: Drain plug stripped

Josh Kiser /

It was the main drain. Thanks for everyone’s help. I am going with the helicoil.

Re: Drain plug stripped

When yer done,flush it out really well.

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