Stripped drain plug, and repaired wrong...some advice
Turbo Mini Forums

its a 998 from teh 80s. When I got the car it was stripped, so I got the correct helicoil and drilled/tapped it, no issues...except for the fact I didnt do it straight, not my proudest moment. It happens to the best of us.

So its off to the point where only one side of teh seal contacts. If I really crank it down it gets close to stopping, but it still has a drip.

Thoughts on repairing? I was hoping (which is a crap shoot) that i could pull the insert out, stuff the tap back in and run it in straight, yeah the threads would be wierd, but maybe I could get the insert in straight? Thoughts on getting the plug in straight? Motor is out, gear box is off and its getting stripped down to rebuild soon. When I got the case empty I wanna get this right. I can do it straight now that its on the bench.

Mark

If the case is off could you just get it tig welded and re-tap for the standard thread? Or just get another case for the hassle it will cause.

That might work, depending how pissed it is, how pissed is it?

If it's tigged it's going to be softer until the material anneals, so leave it a suitable time before retreading.

Other options are, use a counterbore to make yhe surface as pissed as the thread...
Use that techniweld ally solder stuff to braze the hole up and retap.

Whatever you do I'd have it with a helicoil as the tread will be much more durable.

That might work, depending how pissed it is, how pissed is it?

If it's tigged it's going to be softer until the material anneals, so leave it a suitable time before retreading.

Other options are, use a counterbore to make yhe surface as pissed as the thread...
Use that techniweld ally solder stuff to braze the hole up and retap.

Whatever you do I'd have it with a helicoil as the tread will be much more durable.

I think there’s plenty of room round it from memory, I would just go up to a bigger size, probably use something metric, drill out and helicoil it, square this time!!

My sump plug is the same; helicoiled on the piss. I tried dowty washers, tape, etc.
The best fix (not perfect but soooo much better than it was) I did a while back was to put the plug in the lathe (magnet facing the tailstock) and machine a groove in the face for a fat o-ring.

This is the sane sealing principle as a dowty, and I think the only reason it didn’t work perfectly is I machined it with about .75mm protruding.

I need to machine another plug that has 1/3 the dia of the O-ring sticking out. That’ll probably fix it.

I got the gearbox torn down and really looked at it. Looks like I can shave the wind off around there the sealing surface is so I can just flat file the angle in. In the end if it's 1 deg off and seals flat who cares. There is so much meat in the area I'm not worried about it. And if down the line it's really an issue it would have to be plugged, welded and machined flat again anyway. Should take me less than an hour I think and the repair should be fine

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Fixed! Cut off the ears around the drain plug so I could get a flat file on it, then just filed an angle into the sealing surface to match the angle of the drain plug. Didnt take much, tool all of 30 minutes. Done and done!

looks like you've sorted it. Had the same issue with mine and used a dowty washer to solve it