‘78 R100 - I have a leaky oil gallery M12x1.0 blind plug. I want to replace both plugs. The original slotted head plugs are in place. I have ordered 2 new 11111338645 hex socket head plugs.
My biggest concern is removing the old original slotted head plugs. So, … please give me some good tips, techniques, tricks, advice, and/or warnings! I’m listening.
Photos might help.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Check with Kurt at the BMWMOA forum, seems there was a thread there awhile back. I tried to find it but couldn't, he may have better luck.
Also Snowbum's website may have information on removing the plugs. LOL, I know there is stuff out on the web from the past, I just can't get the search engine to find it. St.
Beware! I do not suffer fools gladly! St.
@14724 Thanks, Steve. Yes, I think I found the thread you were referring to. Also, a thread on advrider, or something like that. Also found Snowbum’s words on the topic. Was hoping to find some first hand ABC member experience here. In any case, I’m diving in. I’ve got 2 new plugs coming. Permatex High Temp thread sealant ready to go. Just hope those little buggers will pop loose. No one seems to mention much problem getting the originals out. And, it seems the consensus is, that the rear of the engine can be lifted enough to get to the plug on the left side without dismantling the swingarm or driveshaft. Thanks,Dave
Glad you found the write ups. Honestly Dave, I myself have never seen one of these plugs leak. LOL, so I am afraid I can't give you the first hand member help. Anyway, please let us know how you make out and good luck. St.
Beware! I do not suffer fools gladly! St.
@14724 Steve, I will update this thread when I get the repair done (power of positive thinking). I may take some photos along the way and submit a short write up for the Airmail. It’s gonna be a little while before I get to it.
I have never done this job, but in my Airhead experience I know that BMW uses a machine-cut, straight slot that has parallel faces. This means that if you use a common, home style screwdriver, then these will "cam out" and bugger the slots in the plug head. Sometimes they are buggered so badly that nothing else can be done but drill out the plug. The reason this occurs is that the faces on a home screwdriver are wedge-shaped.
If I understand your screw/plug issue (photos were never provided) then you need to use a straight slot bit that has parallel faces. Sometimes you'll see these available for use on guns, clocks, and other pieces of fine machinery. It's like those, but larger.
When I have been faced with removing the filter by-pass plug deep inside the engine oil filter well (which I imagine to be similar, but there again without photos it's hard to know), I took the new plug and spent 30 minutes forming a bit to precisely fit the new screw/plug. Then the bit made 100% perfect contact, and the old plug came right out.
It's common sense to anyone who has studied Statics. A wedge applied to parallel faces always has a force vector that wants to jack the bit out of the slot. It cannot be otherwise. Whereas a parallel face bit applies 100% of it's force toward turning the screw/plug. And that's what you want to be using to remove a plug that's been in place 40+ years.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
@wobbly Richard, that’s a good idea. Perhaps I’ll sacrifice one of my large flat blade screwdrivers, and grind it to fit exactly as you suggest. Like I said, getting the originals out is my greatest concern. The replacement plugs (BMW #11 111 338 645) are hex socket head - much better. I confirmed on my last long ride that the plug below the oil sender is definitely leaking. It’s very little, but makes a mess over time.
@wobbly Richard, that’s a good idea. Perhaps I’ll sacrifice one of my large flat blade screwdrivers, and grind it to fit exactly as you suggest.
You must !
The angled face of the hardware store variety screwdriver by its very shape creates a force vector that not only robs you of the ability to turn the screw in question with full force, but that will invariably mess up the slot so badly that you may never get the screw out ! Here's a quick cartoon to show...
The shape of the wedge blade, whether desired or not, creates an outward force. Let's say that you are turning with a force of 10 lbs, then if that 80/20 ratio holds, you are really only turning the screw with 8 lbs, while 2 lbs is being totally wasted trying to force the blade out of the slot. The "jacking force" is completely working against your goal. The idiot might simply "double down" and apply 100 lbs of force, but then that only magnifies the jacking force to 20 lbs ! It's wasted energy AND very counter-productive.
Better to have a flat face that engages the straight sides of the screw slot perfectly "normal" (90°) to the turning force. In that way if you apply 10 lbs of rotating force to the plug in question, all 10 lbs is applied toward turning the plug.
Such screwdriver bit sets are available from suppliers, such as Chapman. If you work on clocks, guns, computers, typewriters, or other fine machinery (or you're simply tired of destroying screw slots !) then you might enjoy receiving a basic set for Christmas, HERE. Or investigate their full line HERE.
It’s very little, but makes a mess over time.
Not really a "leak", but more of a unsightly "weepage" or "seepage".
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Follow-up on my own post. I did successfully replace the two oil gallery “blind plugs”. The photo shows the type of bit used to remove the original (‘78) slotted plugs. They actually came out quite easily. The newer version replacement plugs are 6mm hex socket head (much better). For sealant I used Permatex High Temperature Thread Sealant, along with their matching anaerobic prep / activator.
The only frustration in the project is accessing the plug on the side of the engine below the oil pressure sender. (The plug around the corner on the rear of the engine is easy access.). If I were to do it again, I would buy new drive shaft bolts and go ahead a disconnect the driveshaft. This would allow the rear of the engine to be raised further for a better shot at this plug. In my case, I did not disconnect the driveshaft. I did back out the swingarm pivot bolts. With the rear motor mount bolt removed, I raised the rear of the engine/tranny as far as possible. It did not afford a straight shot, but I managed to make it work. It wasn’t exactly pretty.
Time will tell, but I am very confident that the new plugs will not weep oil.
Thanks for the follow up Dave, St.
Beware! I do not suffer fools gladly! St.
Hay, that's great news ! Congrats.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
One more picture (only one I took!) - the rear facing plug on its way out. Removal of this one was easy-peasy.
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