Originally Posted by
FBinNY
The most successful method for freeing aluminum seat posts that are chemically bound in steel frames, is ammonia. You have to try ammonia first, beacuse other methods such as penetrating oils will prevent it from working. Since your post is closed on top, trun the bike over, and pout ammonia down into the seat tube via the BB.
Give it 24-48 hours to do it's thing then put the post in a vise, and try turning the frame.
I just freed a frozen seatpost on a salvaged 1995 Schwinn Cane Creek rigid fork MTB for a friend. Removed crankset and bb, inverted frame in work stand, used hypodermic syringe with a plastic tube (frame had small bb shell openings on inner tube joints), poured in maybe 6 ounces of ammonia (not knowing the seatpost length, but filling up to a bottle mount hole), and waited 72 hours.
It was a LaPrade type seatpost, so had nice parallel sides to clamp into my large bench vice, frame upward. One good twist of the frame, and it gave way. The vice was good for holding the seatpost head as I lifted and twisted the frame, inching the seatpost out of the seat tube.
This method has worked for me before. PG