skuke
captain
Reged: 12/22/03
Posts: 321
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Anybody got a good idea on how to (re)move a stuck seatpost?
I need to lower the seat on my Moser about 15mm. The post has been in it's current position over 12 years. It's an aluminum post in a steel seat tube. There is no binder bolt or seat post clamp and no feasable way of getting any appreciable amount of penetrating oil down onto the post. The seat post locks in place with a wedge like older stems.
I've beat on it with a "dead blow" mallet but am afraid to strike it any harder. It doesn't twist or move up/down. I have ridden it for about 200 miles and had the wedge tightening bolt very loose the entire time. I was hoping the constant vibration and weight (~133lbs) would break it free.
The best solution I can come up with is to find a seat with a shorter distance from the top to the rails. I really need to fix this because I've developed a slight knee pain (top of patella) and I can only attribute it to the slightly high seat.
Thanks,
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Skuke
95 Carbonframes Tetra Pro
92 Bridgestone MB-1
90 Moser 51.151
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flyaway
new member
Reged: 12/27/03
Posts: 9
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You will want to double check this. Take the bike apart find a tub that large enough to hold the frame and soak the frame in ammonia, for how long I don't know. Maybe you could just take the bottom bracket out, turn the bike upside down and fill the seat tube with ammonia . Good luck
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Thomas
new member
Reged: 12/20/03
Posts: 12
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Sometimes a rapid temperature change can cause dissimilar metals that are corroded together to loosen up. Try first packing the parts in ice until they're good and cold and then heating them with a heatgun. (I would say use a propane torch but that might not be too good for the finish (!) Some variation of this technique just might work.
Another more radical solution is to cut off the seat post and then cut through the remaining piece with a hacksaw blade, being careful not to cut into the seat tube (not easy)
Good luck!
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Thomas
new member
Reged: 12/20/03
Posts: 12
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Another thought. If you can remove the "wedge tightening bolt" completely, you might be able to loosen the wedge by pounding on it from above with a mallet and a long shaft of some kind. I'm not really familiar with this kind of seatpost so .....
If the wedge drops out and the post is still stuck, then you will have to use the previous suggestions.
You also may want to take it to a good bike shop. They are usually familiar with this kind of problem.
Thomas
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Thomas
new member
Reged: 12/20/03
Posts: 12
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Another thought. Use a co2 cartridge or two for cooling the seatpost clamp area - that would be faster than using ice and the speed of the cooling/heating is what helps break the bond.
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flythebike
captain
Reged: 08/26/04
Posts: 272
Loc: N. Virginia, USA
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I have successfully solved this problem before. However the post was not in the same position for so many years. First you need a sturdy table with a vice clamp attached. Remove the seat. Remove the wheels, invert the bike and place the seatpost in the clamp.If you don't want to destroy the seatpost then you should wrap it with something to protect it from the vice jaws. Then just grip the frame and fork and gently but firmly rock it back and forth, and you will gradually break it free. If you want to try to get some lubrication in there first to make it easier, remove the water bottle bolts and squirt some tri flow or liquid wrench or something in there with the frame inverted, and leave it overnight (at least). Of course you can remove the BB too if need be to accomplish the same thing.
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skuke
captain
Reged: 12/22/03
Posts: 321
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Quote:
Thomas wrote:
Another thought. Use a co2 cartridge or two for cooling the seatpost clamp area - that would be faster than using ice and the speed of the cooling/heating is what helps break the bond.
Thanks to everyone for the suggestions!
I did some research on the ammonia method and it appeared to be a solution, but it would have required removing the bottom bracket and associated parts. I also felt some risk of damage to the paint.
I decide to use the chilling method since this was the least amount of work, and probably safest for the bike. I wrapped the seat tube with some "bar" towels around the area of the seat post. I poured VERY hot water on the towels. The towels held the water and helped to insulate the tubes and retain the heat. Here comes the fun part! I then went into the lab at work and got some liquid Nitrogen!! Chilled that baby right down!
The seat post broke free with a slight wack of a mallet. I was then able to move it, albeit with some difficulty. I couldn't actually remove it since I need help to hold the bike down and I was alone, but I was able to lower the seat and that's what I wanted to do anyhow. I still feels like it's full of caked on grease, and oxidation, but it moves!
I have the height adjusted close now and I hope if it needs further adjustment, it'll be much easier.
Incidently, when I removed the towels, they were still warm on the inner side closest to the seat tube.
Thanks again for the great idea.
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Skuke
95 Carbonframes Tetra Pro
92 Bridgestone MB-1
90 Moser 51.151
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Thomas
new member
Reged: 12/20/03
Posts: 12
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Great!, glad to hear you "freezed" it up! If you can get it all the way out, it would be good to grease it or coat it with anti-seize to prevent it seizing up again. (Not sure it would last 12 years though!)
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