LANDSURFER74 wrote:Disimilar metal corrosion has been with us for ever;
As previously stated , apply heat and shock even with a 'new' crank arm.
Install extractor , apply torque, heat, shock ( that's hit the extractor with a 4oz hammer, for all those working in the banking industry) , never rely on the extractor removing the crank arm with out a little help, it may well , but if not ....you've had it.
and all you 'hard' engineers out there ..yes a 4oz hammer is all it takes.
easiest way is a ball joint splitter the one with a v and long handle down the back of the chainwheel and whack the joint splitter with a hammer comes off no bother if the thread is stripped as the chainwheel or crank is scrap
if the bb axle has a bolt in thread fitting and you can get the left hand crank off take out the bb cup and put a punch that will fit inside the bb axle bolt hole and keep hitting it with a hammer the shock force will take the bb axle out of the chainwheel.
the usual cause of this problem is some prat none mechanic putting grease on the axle flats usually that crap white bike grease which when exposed to the air goes brick hard the flats of the axle should be absolutely clean no grease whatsoever.
ive been lucky a few times using the remove left hand crank and the punch in the bb axle thread hole method thereby saving the threads in the chain wheel cleaned up the axle flats regreased the bb cups and put everything together job done.