I read about a product called Wurth Rost off Ice... Apparently it freezes whatever you spray it onto to -20'c which does similar to heating... cracking the rust locking the bolt to the nut, and its a penetrating fluid too... so maybe i'll see about ordering some up.

__________________
Ben

'85 500 SEL
'85 928S2
'88 560 SEC
'90 750i