Transmission drain plug stuck

Friends, I need your help. I bought a '96 last year and have been slowly rebuilding it as time and money permit during the pandemic. I've posted on this forum before and found it helpful... I hoping for the benefit of someone's experience. It is mostly complete, but I have a significant problem.

The transmission plug was completely stripped when I bought the bike. I have been unable to get heat on the bolt because as I try to get my propane torch onto the bolt head, the flame cuts out due to the recessed nature of the bolt. Runs out of oxygen, I'd guess.

I have soaked the bolt in penetrating oil and tried no less than three magic 'bolt removal' tools, finally resulting to trying to use a reverse drill. The bolt seems to just disintegrate but does not come out. I have graduated to the largest of the bolt removal bits, to no avail.

My thinking at this point is that I need to remove the transmission and disassemble it and drill out the plug completely and retap it. Or replace the transmission housing. I do need to check/replace the clutch and lubricate the splines on the main shaft coming out of the engine, so maybe I needed to do this anyway. Just means I'm some weeks away from riding, as the beemer boneyard clutch kits are 420, and I also still need to reassemble the gas tank.

Glad for your thoughts,

Derrick

IIRC There is a thread here started by Jim Von Baden with this issue.

GSAddict said:

IIRC There is a thread here started by Jim Von Baden with this issue.

Click to expand...

Here is the link to the mentioned oilhead project -

https://forums.bmwmoa.org/showthread.php?97291-1994-R1100RS-Project-bike

A great deal of elbow grease was used to improve the mechanical and cosmetics about that project bike. Alas, it does not appear that the stuck transmission drain bolt was able to be freed. The old transmission oil was removed by suction from the fill port and new oil was added. [Post #141 in that thread shows the stripped drain plug.]

Heating the plug and expanding it won't help get it loose. You have to shrink the plug while heating the transmission housing to get the benefit of thermal expansion(s). You might try to momentarily put an ice cube on the plug, then torque like hell, after everything else is heated.

I would invest in a Harbor Freight heat gun for the case and some freeze spray for the bolt. https://www.amazon.com/BW-100-Freez...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

nrpetersen said:

Heating the plug and expanding it won't help get it loose. You have to shrink the plug while heating the transmission housing to get the benefit of thermal expansion(s). You might try to momentarily put an ice cube on the plug, then torque like hell, after everything else is heated.

Click to expand...

IF you can get something to hold the plug tight, ez-out or similar, try warming the case with a heat gun and then blast the plug with freeze spray. This might create enough of a "shock" that nrpetersen is referring too.

While warming the case, tap on the ez-out with a small hammer.

Using a t-handle on the ez-out can be a little extra help.

Barring all that, if you are or know of a good welder, weld a big nut onto the plug.

Valve grinding compound

Find the tightest fitting easy-out and apply valve grinding compound to its teeth and sides but not the tip. Drive it in, use a heat gun around the case where the plug is screwed into it and get the temp up to about 200 degrees. then give the easy -out some firm but gentle tugs with the appropriate size wrench, a 1/2 drive 18 inch long ratchet would be best for this job. Its important to keep a firm grip on things and keep the easy-out steady and straight while you apply pressure. It worked for me!

Once when I had a damaged fill plug that would not work with an Allen key, I cut a slot into the head and used a hammer and a big screwdriver to rotate it out. Of course in your case, with it being stripped, the above suggestions might be more successful.

Please let us know how it eventually turns out. (no pun intended)

Any pictures?
OM

trigger warning... it's bad.

Thanks. That’s a tough one. I have nothing practical to offer that wouldn’t be rather risky.
Good luck.
OM

Drill all the though with a small bit, 1/8" or so.

Keep going larger until you can get one of these in:

Find a socket the same size as the driver and an impact gun. Turn the gun down to minimum, lower air pressure if you can and let the gun hammer away on low for a bit.

The oil will keep you from getting any real heat into the area. You need to get the oil out even if it means tipping the bike over and letting it run out the fill hole.

Is the head of the plug broken off? Can't make complete sense of the pic. Striking the plug is good because it can crush the washer (if there is one) and unload the threads a bit. However, if it was originally a 6mm allen, there probably is no washer. Those plugs are tight. Drilling offcenter really makes for a tough repair.

dieselyoda said:

Drill all the though with a small bit, 1/8" or so.

Keep going larger until you can get one of these in: View attachment 83696

...

Click to expand...

I've ordered some of these doo-hickeys.

Summing my thoughts with some of the others: I would drill totally through the plug. I would then insert an extractor - mine are a set of Hansen brand screw extractors. I would tap/drive the right size into the drilled hole. Obviously, as soon as the hole is drilled the transmission lube will drain out. I would then heat the case. Once the case is heated I would unscrew the plug using the extractor. Modest impact from a decent impact driver would help.

Once the head is off the plug, the rest will unscrew easily. Based on the pic, there's no reason not to just try to drill or grind the head right off.

Another happy forum customer

Well done.

derrickstone said:

View attachment 83803

Click to expand...

Great!

I’m not familiar with that kind of easy-out. All mine are a “tapered flute” or “reverse spiral”. Do you have a brand/type name for those extractors?
Thanks.
OM

The devices shown above are straight flute extractors. A set can be purchased from McMaster-Carr -

https://www.mcmaster.com/straight-flute-extractors/straight-flute-extractor-sets/



Amazon has something similar called a Walton flute tap extractor. These are available in either a 3-flute or 4-flute configuration. Extractors are available individually or in sets -

https://www.amazon.com/Walton-18003...ywords=flute+extractor&qid=1622381341&sr=8-18

https://www.amazon.com/flute-extractor/s?k=flute+extractor