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PostPosted: Sun Oct 20, 2013 9:38 pm 
Retro Guru

Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
Nomads wrote:
FINNEY1973 wrote:
May work? - Drill through the seatpost at 90 degrees to the frame and stick a very long threaded bolt & nut arrangement through it for leverage - my dad did this for me years ago and it worked a treat - I seem to recall the bike was held in a vice and the bolt must have been a metre long? It was some contraption but it got a very very stuck post out.


If the frame is special please don't do this.

many people try this as a quick fix, but it put lots of stress on the tubes including the rear stays, why risk twisting the frame?

Steel posts in steel frames can sometimes be done this way, but alloy posts generally welds itself to the inside of the seat post tube. It is either cut it out or melt it out / dissolve the alloy post.


Fair comment Nomads - I can't recall whether it was a steel or alloy post, just an idea as the OP seems to have tried products and to no avail - time to call the experts in with the right tools and know-how perhaps.


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PostPosted: Sun Oct 20, 2013 9:48 pm 
Devout Dirtbag

Joined: Tue Jul 30, 2013 10:06 am
Posts: 125
Location: Nottingham UK
I have a Black & Decker hot air gun which I use together with Plusgas and have been successful on several occasions. Gently heat the seat tube - its only like a big hair dryer so it doesn't damage the paint as long as you are careful - and twist the tube with a mole grips or similar. If the alloy is heavily corroded it won't work but in many cases it is enough to get the post moving.
Good luck!
Dave


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PostPosted: Sun Oct 20, 2013 9:58 pm 
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Joined: Sun Mar 17, 2013 10:25 pm
Posts: 1262
One of the tricks a motor mechanic would do before loosening a seized bolt or nut is to crack it tighter first to break the seal. My suggestion since the OP has been steeping the post with various concoctions would be to remove the saddle and using a block of wood on top of the post hit it inwards with a 4lb lump hammer, one hard sharp blow should be enough to break the seal.


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PostPosted: Mon Oct 21, 2013 8:57 am 
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Joined: Wed Apr 25, 2012 2:08 pm
Posts: 2185
Location: Shrewsbury
If its truly stuck, which by the sound of it yours is, you need to cut it out. Its actually not as bad or difficult as it sounds and I've removed a fair few with the following method. Apologies for the CTC link, it saves me writing and uploading all over again! :lol:

http://forum.ctc.org.uk/viewtopic.php?f ... +seat+post

Don't try and just twist it out in a vice. I had a friend do that and the sudden crack sound wasn't the post freeing up :facepalm:


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PostPosted: Mon Oct 21, 2013 12:34 pm 
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Joined: Mon Sep 24, 2012 9:10 pm
Posts: 667
If you decide to cut it out, Robbied's link gives you an idea of what you're up against. Here's another, the top of an SR Laprade, the bottom of which I had to cut into quarters, many years ago, before I could free it. I wish you better luck, skill, or both..
Image

If it's an alloy post, and you have any sensitivity, you will both hear and feel when the hacksaw teeth have reached the inside of seat-tube- but despite that, I still have a small hacksaw-blade sized scar on the very top-inside of my seat-lug from this operation. It's good to have a few mementos to remind you of the benefits of grease, just as it's good to have rationalisations to make you feel better about your mistakes.. :|

Roadking- A minor terminology nitpick.. I don't want to raise your dudgeon with this, but IMO, a seatpost should ideally be slacker than a true interference-fit. To me, an interference-fit is a fit that is designed not to move, and needs a hammer or press to dismantle. It may be interference-fit seatposts (and lack of grease) that cause such siezures in the first place?


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PostPosted: Tue Dec 24, 2013 10:12 pm 
Dirt Disciple

Joined: Sat Oct 05, 2013 10:26 pm
Posts: 29
Finally, after 6 weeks with the seat tube full of plus gas, a lump hammer and two helpers the 32 year old seat post is out. Frame is intact!

Merry Xmas :xmas-wink:


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PostPosted: Tue Dec 24, 2013 11:01 pm 
Retro Guru
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Joined: Thu Jun 23, 2011 11:25 pm
Posts: 1785
Location: It's not easy being a dolphin.
Nob wrote:
vice table bolted to the floor synthetic sling & a 16T Demag overhead crane. The tools I used on a frame to remove a seized seatpost a few years ago


Not that I have a 16T Demag overhead crane knocking around in the bottom of my tool box, but could you elaborate on this?

I'm assuming you fixed the BB shell (somehow) in the vice and managed to pull vertically up right? How was the sling attached
to the post? I've often thought about building a jig using an hydraulic car jack for such purposes.


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