Old 07-04-07, 09:29 AM
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dbohemian
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I have fixed this many a time. It is a pain, no doubt. You are correct in that the post is corroded into the seat tube. Essentially it is poorly welded in there.

Let the penetrating oil work a while (like a week).

Next, get some way to hold the bike very well and then get a big assed pipe wrench and honk back and forth on the post, this will destroy the post, but rarely is there any choice. If it lets go at all you can add some more oil and work it out of there with back and forth movements.

If this doesn't work you are going to have to cut it out. Cut the post off near the top of the seat tube and then get a slitting hack saw and make 4 cuts around the inside of the post until you have nearly gone through the aluminum but not all the way through. Then take a big drift punch and hammer one section out. Once that is done the others should come out fairly easily.

Some try the cold treatment also. That is freezing the aluminum with CO2 or dry ice etc. Aluminum contracts more than steel so this may help, but it never worked for me because the corrosion holding the two items is usually too much.

Hope that works.

Dave Bohm
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