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1989 R100RT exhaust nut removal

S

Scarletswirl

New member
I just acquired an '89 with a little over 40K miles. I need to reseal the pushrods, but I'm having trouble removing the exhaust nuts, which is the first step. All I've read so far indicates that if they are stuck, cutting them off is the only way out.
1. At what point should I give up and call them 'stuck'? In other words, are there tips and techniques that can be used to loosen these nuts, besides brute force?
2. Is this (i.e. exhaust nut cut-off) something any of you who are not professional mechanics tried successfully. I would hate to do anything that will result in permanent damage.
All thoughts and ideas appreciated
Thanks
Marc
 
Soak them daily in a mix of acetone and automatic transmission fluid for at least a week. Then apply heat with a propane torch. You will need the specialty wrench.

Tom Cutter gave me this method and the nuts on my '76 R90S popped right off when it was 40 yrs old.
 
CCOLWELL
He's got it.
Soak 'em for a week then get a torch and get 'em HOT and they will come off.
Heat rises so I heat the tops of the nuts first and then the bottoms / sides, the trick is to get 'em hot.
Put 'em back on with COPPER based anti seize. The silver stuff isn't suited to the high heat there and that big area of threads.
Nick
1978 R 80
 
I had mine strip when I removed them. If they don't come off easy, I'd vote for cutting them before you strip the heads. It's not cheap to have them repaired.
 
Thanks for all who contributed. Report after day 1:
Using a syringe, I injected several drops of a 50/50 mix of acetone and ATF, aiming at the threads, getting them from the front and from the back. I did this 4 times and will continue 4-5 times a day. After the last time, I tried the wrench, just for giggles. The right side started turning and is now off. I put it back by hand, just a few threads. The left is still stuck, but perhaps it's because it's because I'm hitting it from the bottom up and it's not as good a blow. Regardless, if I keep it up and eventually use heat, I might get lucky in time. Either way, you already saved me the expense of one exhaust nut.
Thanks again
Marc
 
Untitled.jpg

Only 4 days of soaking and no heat. Exhaust nut got a bit mangled, but I already ordered two new ones anyway.
Thanks again
Marc
 
Scarletswirl said:
Either way, you already saved me the expense of one exhaust nut.
Thanks again
Marc
Click to expand...

And when you get the other one off, don't just apply an anti-seize and reinstall the exhaust nuts when the job is finished. Clean up the threads on the exhaust stubs and in the exhaust nut, then apply anti-seize.

Right%20Cylinder%20Head%20Exhaust%20Stub%20-%203-XL.jpg


Exhaust%20Nuts%20-%204-XL.jpg
 
I initially used the whammy-dyne laser cut EME tool. Worked on the right side, but it's too thin and it started distorting/deforming. Result: instead of turning, it mangled the fins. Then I bought the Siebenbrock (sp?) tool, which looks like a massive casting and engages one fin every two. That one is more solid and has a longer lever arm. Worked after a few days of soaking with the magic brew (acetone+ATF).
As far as the threads, yes, I absolutely intend to clean them up! I was going to anyway, but I appreciate the suggestion
Cheers
Marc
 
Hinted at only, but the thing is they should be installed with a high temperature antiseize compound applied to the threads.

The usual German standard is Optimoly Paste TA, which is silver and looks better than copper color in this application. Use it on all exhaust system joints.

This product now belongs to Castrol and has a modified name ... available from BMW 83 19 0 447 919

moly.jpg
 
lkchris said:
The usual German standard is Optimoly Paste TA.
Click to expand...

Which has now been renamed to Castrol Molub-Alloy Paste TA as per the attached PDF.

I just use anti-seize on my exhaust stubs and nuts and they always come off, but happen to have tubes of the above product for my Porsche Centerlock nuts since that is what they call for.
 

Attachments

  • Castrol Molub-Alloy Paste TA - 2014-12-23.pdf
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