I thought I'd better change the gearbox and final drive oils on my new to me 1150gs, according to the service booklet they were last done 1500 miles ago, unfortunately that 1500 miles ago was in 2016. The plugs are stainless steel and they are stuck, I've tried heat, tapping them with a hammer, a fiend is going to lend me his impact gun and allen key bits, any other recommendations? I've got a mig so I suppose the final solution is to weld a nut to the plug, luckily i tried the filler plugs on both first so I can still ride it.
Stuck gearbox plug
- Thread starter jobjobbed
- Start date
boil a big kettle of water and pour it over the alloy You want the alloy hand hot by the stainless plug but pour around the plug rather than over it ! You want to heat the alloy not the stainless!!!
work away with maybe two or three kettles worth
Cover it with a towel or blanket to keep the heat in
Hit the plug a decent rap with a hammer nice and square through the centre line of the hole
and then with a DECENT hex bit and a three foot bar try to loosen it !
P.S. don't use coppaslip Get alloy antiseize for it !
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Whilst I have not had the misfortune to need to try it, I hear good stories of this plumbers spray: -
when you have done the boiling water bit , spray brake cleaner into the hex hole , this will cool it , and shrink it a little
do NOT use the impact anything on it.
do NOT use the impact anything on it.
I would’ve thought a heat gun would be sufficient. The alloy will expand more than the steel. It could also be a bunch of loctite (BMW mechanics have a penchant for this) and the heat will soften that too. 
PS. Hairdryer won’t cut it - you need a heat gun.
PS. Hairdryer won’t cut it - you need a heat gun.
Nope the steel soaks the heat up and retains it and just tightens everything as it gets hotter, faster than the alloyI would’ve thought a heat gun would be sufficient. The alloy will expand more than the steel. It could also be a bunch of loctite (BMW mechanics have a penchant for this) and the heat will soften that too.
PS. Hairdryer won’t cut it - you need a heat gun.
Boiling hot water is a better optionI would’ve thought a heat gun would be sufficient. The alloy will expand more than the steel. It could also be a bunch of loctite (BMW mechanics have a penchant for this) and the heat will soften that too.
PS. Hairdryer won’t cut it - you need a heat gun.
Okay, cool your jets?! lol
Guess I don’t have much experience working on older stuff. My biggest issue’s been with hardened blue loctite.
I bow to your superior knowledge
Guess I don’t have much experience working on older stuff. My biggest issue’s been with hardened blue loctite.
I bow to your superior knowledge
The gearbox has a second drain plug, a flat plug located on the bottom of the gearbox, undone with a 14mm hex socket.
If the cat is still fitted you’ll need to remove it to get to the plug, I think it’s easily accessible if you have a Y piece.
On the BMW R1100S gearbox it is the only drain plug. Due to tight clearance with the exhaust header, i have a shortened 14mm Allen tool or a 3/8" coupling nut (filed to fit) is often needed.
If the cat is still fitted you’ll need to remove it to get to the plug, I think it’s easily accessible if you have a Y piece.
On the BMW R1100S gearbox it is the only drain plug. Due to tight clearance with the exhaust header, i have a shortened 14mm Allen tool or a 3/8" coupling nut (filed to fit) is often needed.
It's got a Y piece, been busy farming today, I'll have a look tomorrow or over the weekend
This chap should be able to help if the hot water doesn't 
I have a short 14mm hex piece, it fits into the gearbox drain plug no matter what exhaust is fitted, I then use a ring spanner on the small piece of protruding hex piece
Make sure and Free up the Fill Plug, before you drain it!!
That gets interesting really quickly!
I had a couple of those to do
A good lashing of HOT water and a firm rap with a decent hammer and Robert would be your fathers brother!!
If it comes to that I suppose I could empty the petrol tank then hang it upside down from the telehandler and fill the gearbox and final drive from the drain plugs
Ffs…………or ride it up to London to see @Steptoe ??!! lol
If you were in the middle of nowhere, laying it on its side (one side will probably be better than the other depending where the plug's located) might be a perfectly good idea.
Would the same process with hot water work for a stuck final drive oil filler plug as well? I've got a 1999 R850R and the plug won't budge. Tried the knocking in a torx and will tackle it this weekend with a long breaker bar. Bike is relatively new to me and the last record of the FD oil being changed was back in 2017 - don't think it's been opened since then!
Pale Rider
Registered user
To save any possible damage/dramas just leave it in place and use a large suringe with a tube fitted and suck out what you can from the filler plug hole and top back up, job done.
Pale Rider
Registered user
Very lucky, you could have easily ripped the bottom out of your gearbox using one of those, but it’s done so you can breathe a sigh of relief now.
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