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seatpost removal / replacement

Old 03-21-12, 12:45 PM
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GuttingJob
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seatpost removal / replacement

i have a stuck seat post that i haven't been able to remove. i am in the process of sawing it out. how far should i cut down before i bend it inwards? what kind of seat post should i replace it with? (mid 80's bianchi)

sorry missed focus


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Old 03-21-12, 01:10 PM
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You pretty much need to cut all the way through and make two peices of seat post. I just got done doing this with a stem and it is really tough holding that hacksaw blade while cutting. you also have to he real careful not to cut too much of the post.

Hopefully the size mark will still be readible on the post when you get it out. otherwise you will need to measure it some good calipers. on that Bianchi I suspect it will be a 26.8 since it is an Oriental model.

You may want to try and use some sort of flex hone to clean up the tube a bit before inserting a new post. I use a brake cylinder hone from harbor freight.
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Old 03-22-12, 03:05 PM
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i sawed it as best i could and tried to loosen it a bit with no luck. i have damaged the protruding post quite a bit. i think i might need to take it to someone in a machine shop of sorts
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Old 03-22-12, 03:28 PM
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I recently gave up cutting a steel seatpost out of an old Gitane frame after spending hours with the hacksaw. Got the aluminum stem out by cutting it but it was a bear.

Did you try putting the post in a bench vise with the frame upside down first? This method has worked the best for me. There is probably still enough post left that you put in a vise. Otherwise I would have a machine shop drill it out to save the frame..
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Old 03-22-12, 03:57 PM
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I don't see any evidence of penetrating oil being used.
Did you use any?
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Old 03-22-12, 04:09 PM
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what has worked in the past is to use Cola. I drink Diet Coke but use Pepsi for this task. Superstition perhaps. Take out BB, flip frame upside down and with intact seat post it was possible to pour cola into the BB and fill the bottom. Leave overnight and the post will fall out in the morning. With seat post cut like this, maybe a regular spray inside once an hour for 5 or 6 hours might be needed. The phosphoric acid in cola is a mild acid that will dissolve rust and gunk and free up the metal. Then flush with water and let the tubes dry and you should good to go. YMMV.
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Old 03-23-12, 07:04 PM
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the only liquids i have tried were wd-40 and ammonia. i will try oil and cola and bench vise before i bring to machine shop
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Old 05-13-12, 09:13 PM
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Originally Posted by Bianchigirll View Post
Hopefully the size mark will still be readible on the post when you get it out. otherwise you will need to measure it some good calipers. on that Bianchi I suspect it will be a 26.8 since it is an Oriental model.
i have found somebody who is drilling the left overs out for me. it would be hard to measure the inside diameter since i have the tube spread open a bit. not sure if 26.8 or 27.2
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Old 05-14-12, 10:32 AM
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he said that the old seatpost measured 26.4mm, do you think he is off a bit?
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Old 05-18-12, 07:27 PM
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just like to let everyone know i fixed it. ended up using a 26.2 mm seat post, and just tightening the bolt as far as i could and its fine.
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