Snapped bung on gearbox fill plug

[derDoug]

Hey guys,
Just today I was going to change the gearbox oil on the 80 and I noticed the fill plug had no washer/gasket on it, thought nothing of it and went to loosen it and just snapped right off, is getting a new bung welded back on my best option? Last picture is how far I can get the new plug in before it clashes with the box and it is not a flat surface

Cheers fellas!

 

[robnicko]

you could use a filler like liquid steel etc on that.
they way the new bolt has exposed threads gives you something to mould the filler around. Just make sure its really clean and press the filler firmly onto the exposed bolt threads so it naturally makes the internal thread- with that new bolt or the old one set in like that hit it with a wire brush all around so the is a good surface for it to adhere too and doesnt get any muck into the box.
Once this stuff sets and hardens can be drilled/tapped/sanded/painted and is very strong. Being the fill plug doesnt need any super torque on it, just enough to hold & seal.
I did a fix on the engine case of my dirtbike with that stuff over 10 years ago and its still holding fine.
They sell it at Bunnings / autobarn etc

https://www.bunnings.com.au/selleys-110g-knead-it-steel-epoxy-steel_p0352313?store=6300&gad_source=1&gclid=CjwKCAjwrIixBhBbEiwACEqDJe2gl2OKzkLhu3EP27tweecvCtbdTEfcouMslvNnarIlkOe7NpwSOhoCSHYQAvD_BwE&gclsrc=aw.ds

 

[mudgudgeon]

I'd be inclined to grind, file, sand the surface flat, and reinstall the plug with a fibre washer (or suitable rubber oring - oil rated)

Be super careful not to over tighten.

Looks like there's still 4 full threads if you are able to flatten the casing.
Getting it flat enough, and square to the plug head would be the challenge.

Block the plug hole with something so filings don't go in the box

 

[mudgudgeon]

Or, what robnicko said

 

[ChargedSHOTaco]

Get a thick rubber washer that compresses slightly when tightened, and call it good. It should be enough to seal it up. You are more likely to screw it up trying to “fix” it.

 

[JoeCova]

I'd be inclined to grind, file, sand the surface flat, and reinstall the plug with a fibre washer (or suitable rubber oring - oil rated)

Be super careful not to over tighten.

Looks like there's still 4 full threads if you are able to flatten the casing.
Getting it flat enough, and square to the plug head would be the challenge.

Block the plug hole with something so filings don't go in the box

This was also my first thought. Only need 3 threads so grind flat for the plug and use some kind of washer.