One thing to be VERY careful about when restoring the threads on one of these sumps is to make sure the work is done exactly perpendicular to the sealing surface, otherwise the result will never seal right (BTDT). It is common for oil change shops to do this when they strip out the threads on people's cars, and if it happens to you then you've got an un-sealable drain.

It can be corrected, though, by re-facing the sealing surface to match the new angle of the miss-drilled hole (BTDT, successfully). Luckily, the cast aluminum thickness around that hole is quite thick, giving lots of material to work with.

Norm

You got it right.  After closer inspection, I found the sump threads are kind of messed up.  Somehow the plug screws in smoothly, but I dared not crank on it hard.  So basically I put the plug back on with a rubber air conditioning oring, and tightened until the oring was nice and squished but not crushed, then put the bracket apparatus back on for safety.  So far no leaks.  Now I'm not too sure about going back to standard plug and trying to rethread.  Might cause more problems than it's worth.  I'll live with a very unique oil plug and funky bracket.

Perhaps a pipe plug is what was used.  I'm not used to seeing them with flat, cylindrical heads except for BSPP (G) straight threads.

Until you buy a new drain plug from our host you could still buy a short 5/8-11 bolt from the home center and use it with one of the Dorman washers I mentioned previously.

They swapped that out for a tapered thread plug (one which uses the threads themselves to seal).

And, somehow it worked.

Well, it sort of worked. Then they had to rig up that apparatus to hold it to keep from turning, apparently (probably because the threads didn't quite match, one is tapered and one is straight).

Norm

You need the BS/Whitworth ratchet to fit :-). I would grind down an old ratchet extension to fit and tighten it with that in the meantime, or weld a bolt head onto it. The US cars/trucks i have come across with differential plugs like these used a 3/8" ratchet, they must be slightly larger.

I've come across similar plugs on Rolls-Royce and Aston Martin cars. Square plug was too small for a 3/8ths ratchet end. I found a used square lathe bit that fit perfect and kept in in my tool box for such problems. Should be able to go back to standard plug, providing threads in sump are fine/ok.

Did find a tool in a catalog to fit the plug, didn't need it often enough to justify buying it though.

No, I didn't mean the plug has fine threads.  I meant the threads are fine (as in they are ok, not damaged ).  It has the standard threads.  I believe the sump threads are ok too.  I tried to find another 5/8-11 plug with a standard head in the local auto stores and was not successful, nor was I successful in finding a suitable tool.    I will just put it back on with a rubber oring and tighted with a vicegrip, and order a new one from our host and permanantly fix the problem at the next oil change.

I don't wish ill-will towards anyone.
But, I sure hope you didn't just jinx yourself into a stripped oil drain hole.

"Easy" is a term I've never heard to describe fixing it.

that is so easy to re-thread, and just look for a next size machine bolt that'll fit in it.  i've done it before on my mopar.

for a fabricator like me, it's an easy fix. no sweat!

Wouldn't it be posslble to just weld in that entire corner from a junked sump?

Or heck, just weld plate over it and tap.

I missed this thread in its first go-round.  

While the plug is out, inspect the threads in the sump and on the plug.  You said this odd plug has fine threads.  The original sump tap would be 5/8-11 which is coarse.  If the odd plug is larger than that, I hope it is not larger by much.  You do have to have some meat to tap for the HeliCoil.  

You can check the threads left in the sump by going to the hardware store and buying a 5/8-11 bolt.  Try running that in to confirm that the sump threads are still there.  Hopefully they will be so you can use a standard drain plug.  Zippy and I use bonded metal rubber seals on stock drain plugs (Dorman/Motormite 65629).  They seal well with low torque compared to the copper washer.  

If you find you need to install the HeliCoil and a new drain plug, be very careful during the installation to keep the drill bit and tap perpendicular to the washer spotface on the sump.

Well, I finally got around to changing the oil and I think now understand why the PO went through all the trouble (not that there weren't other easier solutions).  The drain plug is very weird.  It does have a magnet, but there is no tool I could find to fit the square hole.  1/4" socket wrench is too small, 3/8" is too big, and standard six sided allen wrenches don't work.  Plus local car shops don't have that size thread replacement plug.  So I think the PO just used a vice grip to loosen, and put the bracket on for safetly since he couldn't tighten much.  There was no gasket used.  I believe the threads are fine.  Funny thing is the plug was not tight at all and not leaking at all, and had to be turned until about the very last thread before any oil came out.  I tried finding a replacement locally but couldn't.  I think tightening with a visegrip and putting a rubber oring should hold me until I order a replacement for the next oil change.

That picture looks like someone has engineered a different plug with a safety measure built in as he has had one come loose before. I would change it for the correct plug as i doubt the one installed has a magnetic tip on it which you need to catch any meatal debri foating around the gearbox.

The picture makes the allen key hole look round but it's actually square, although you might be right that it could be stripped enough to require use of pipe wrench on the outside.  My guess is that because the bracket is in place they couldn't turn the plug with a normal allen wrench from the side so they used a pipe wrench or vice grip from the bottom.  There looks to be some type of metal gasket seal between the plug and housing.  The oil leak is definitely from somewhere else, as it is pretty wet well above the sump.  I don't see any drippage from the plug.  

Nahhhh it doen't fit a scooter and too nice for anything he would come up with :-)

That is strange. I also looks like the allen key/hole is stripped. Might just be the picture but could also explain the bite marks on the outside. I dont really get how this would even work?? The original needs a copper seal to ensure its oil tight. What does this use? I mean, I get what they tried to accomplish with the "safety lock" thing but how does that plug actually seal? Its pretty wet down there, is the oil coming from the drain plug?

Yeah weird. (It looks like something you'd find on a certain patchy pink Mini.)

It just seems crazy to me that someone would go to those lengths just to ensure the plug doesn't loosen.  I've never heard of a modestly tight plug ever coming loose.  The bite marks on the outside of the plug also worry me.  Looks like someone tried to use a vice grip instead of an allen wrench.  Just seems like a rube-goldberg solution for whatever the original problem was. 

jwakil, I'm not sure it's a complete mess or someones clever solution.  The drain plug looks to be a newer style allen plug.  Maybe clean it a bit more but it looks to have a sealing washer as normal.  The welded bracket is a gearbox stabilizer that's been modified, right?  They did this to insure the allen drain plug can't loosen and fall out - hence the screw with it's locknut.  It's possible they did this instead of drilling and safety wiring a standard drain bolt.  Maybe to pass tech inspection for a racing event?  Who knows?

It's certainly not stock and when it's time to change the oil you'll discover whether the original sump threads are still intact.  But it's effective and pretty clever IMO.  And not hard to change back to stock as Alex suggestes.  

The time and money they spent on that, they could have just fixed it the proper way. Gotta love people.....