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Stuborn stuck AL seat post in CF frame

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Stuborn stuck AL seat post in CF frame

Old 03-11-11, 02:16 PM
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Stuborn stuck AL seat post in CF frame


I have a 2008 FUji team frame that the OEM 27.2 AL seat post had become forever stuck inside. I worked my way through the sheldon methods, sacrificial seat, ammonia on seat tube, upside down in the vise, etc. with no luck.

I decided to try the hacksaw method, so I cut the post off leaving an inch above the seat tube. I made the cuts and tried to collapse the post with vise grips. Maybe I was too scared to cut deep enough or maybe it's just REALLY stuck, but all that got me was removing the 1 inch of seat post material above the seat tube.

So now I have a seat post down in there with no real way to grab onto it. I've tried to do some reading decided what the next attempt would be before I give up on the frame. I read that some people have used adjustable hand reamers to remove seat posts.

Basically I am asking, is this the next step I should take? Is there anything else I could try before buying this tool?
If that's my only next step; I know harbor freight tools suck, but would one from there be sufficient since it will be the only time I will be using this tool? Also, what cutting fluid should one use that would not damage the carbon?

Also, i guess I should ask this. do LBS shops typically have this type of equipment if I whimp out and want to pay someone to try and ream it out?

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Old 03-11-11, 03:10 PM
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I'm not a bike mechanic, and I'm thinking outside of the box here. Hell, I don't even know where the box is. Here's my solution.
1) Find somebody with high quality micrometer that will measure the inside diameter of your old seat post.
2) Buy a seat post to fit inside the old seat post, and test fit it on the cut off piece of old seat post.
3) clean up the edges of the old seat post / seat tube with a small round file. Any chainsaw file will work here or a drum sander on on a dremel. If you want to get really fancy, after sanding, polish the inside with a brake cylinder hone.
4) Lubricate the seat tube and insert the new seat post into the frame.
5) sit back and admire your handiwork while drinking 10 to 12 beers, then go out for a test ride.
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Old 03-11-11, 03:18 PM
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Take a hacksaw blade with a blade holder and cut down the split in the frame as far down the inside of the seat post as you can go. I have also used a quill stem to grip the post at the top and use that as a pipe wrench to spin it out. Take your time it might take a couple days to loosen this up with the ammonia.
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Old 03-11-11, 03:18 PM
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With the hacksaw you should have cut through the full length of the remaining post. The resulting slot would allow the post to close in or collapse enough to come away from the seat tube walls. It doesn't sound like that's what you did. You could still try that.

Reaming could get tricky if the cutter drifts off center.
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Old 03-11-11, 05:04 PM
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Removing a frozen post from a carbon frame is very different than if the frame was steel. The carbon seat tube won't take as well as a steel one to most of the brute force options.

My suggestion is to pay a decent shop to ream it out with an adjustable blade reamer. You'll have to do some prep work with a half round file to create a taper or bellmouth at the inside top so the reamer can easily pick up the axis of the seatpost and follow it down.

Most decent posts are concentric inside and out so once you establish the alignment, you can take off a few thousandths on each pass. As you near be vary careful and sight down the tube after each pass to make sure you're not breaking through one side and reaming the frame.

BTW- you can do this yourself, but you have to factor the cost of one or possiblw two reamers into the cost. Measure the current post ID, and the final ID, ie. 27.2mm and see if you can find a single reamer with the right range. Metric or inch doesn't matter as long as the size range is OK.
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