Originally Posted by
jp911
Trouble with PB blaster is when there's simply no space for it to even get into the affected area. Ideally you would be able to soak the entire seat tube in PB, but that's pretty difficult.
You could try this: If you have enough seat post exposed, try to knock the post (with a 5 lb sledge on a wood block and the frame resting on wood or some sort of padding softer than concrete) deeper into the frame. The idea being that you might break the bond between the post and the tube. Heat and cold sometimes help, but you could really damage the paint and just find yourself more frustrated.
I tried using the pipe wrench to bang the seat post down, but that was fruitless. I also tried banging on the outside of the seat tube thinking it might break the aluminum oxide free, but that was also no help. I was thinking of trying to use a ratchet strap to get leverage on the seatpost and pull it down into the seat tube that way, but I'm afraid I'll damage the frame. I think it's time to consider that this is the seat post's final resting place.