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How to remove a seat post

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How to remove a seat post

Old 03-04-06, 12:43 PM
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Dave87
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How to remove a seat post

Hello, I am new to this site and also new to fixing bicycles. About a few weeks ago I just purchased a Giant Rincon SE mountain bike at a flee market and planned on giving it a new paint job. I removed the wheels, handle bars, seat,and breaks from the bike but am having a bit of difficulty removing the seat post. I heard a couple of ideas such as applying ice and a cold wet rag arround the post to weaken it's bond, as well as the idea of putting the bike on a vice and applying ammonia to the post, both of them producing little results. Is their any other ways to remove a stubborn seat post? Your response would be greatly appreciated.
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Old 03-04-06, 02:25 PM
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MacG
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Make sure the binding bolt or post clamp is loose (heck, take it all the way out/off) and spread the clamp with a fat screwdriver. Sometimes people will overtighten seatpost bolts on steel frames and deform the seat tube so much that it will bite into the seat post. I've had the best luck from reversing this force with a screwdriver or small pry bar. If you have an aluminum frame and/or post, ammonia might be just the ticket.

After you get ammonia or penetrating oil soaking into the seam and have relieved any pressure on the binding bolt and spread the tabs, try removing the seat from the top of the post and tapping the seat post deeper into the seat tube. Be careful not to overdo it, but once you get it broken loose downwards you might have a much easuer time at getting it to come out.

Some people have been known to drill a hole through a stuck seatpost and use a bar or rod of some sort as a wrench to try to rotate the seatpost. A pipe wrench would probably work as well. You run the risk of snapping the post off by trying these destructive methods, and if you break it off very close to the seat tube, you've pretty much ruined the frame unless you can come up with some brilliant way to extract the still lodged stub or can get a machinist to bore the tube out without ruining the frame.
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Old 03-04-06, 06:12 PM
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Search here and on sheldonbrown.com.
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Old 03-04-06, 06:30 PM
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If you break it off near the frame, a sawzall would cut a slit in the seat post w/o damaging the frame if you're very careful and patient. Just get a thin blade that you can stick down the hole.
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Old 03-05-06, 07:35 PM
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Besides using a penetrating liquid that might free up the space between the post and the inside seat tube, I would suggest keeping the seat on in order to give you leverage while trying to twist the post up. I always found that it was easiest to remove a stuck seat post with the wheels, crank, and pedals still on. Putting your foot down on the down tube of the frame right near the crankset and grabbing and twisitng the seat gives you a lot of leverage. The more parts that are off of the bike the less leverage that you have to pull the post up and out. Other scenarios are , if and when you have removed the crank and bottom bracket spindle, put the frameset upside down and pour penetrating oil from the crank bottom brakcet down into the what is now bottom of the seat post. Let it sit for a day and try all your Herculean efforts again. Good luck. Hope it does not get as bad as utilizing cutting tools.
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Old 03-05-06, 09:15 PM
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okay had the same problem not even a year ago. do this exactly and you'll be just fine.

'87 scott boulder -- cro-mo frame w/alloy post: removed saddle because the seatpost head was broken and it spun in place; this was a TOTAL rebuild, so everything was off (bare frame); drilled two parallel holes into post about 2 inches above seatpost binder; use screwdriver to pry open binder bolt eyes a little; put bike in shower upside down and poured full strength lemon ammonia into bottom bracket to penetrate underneath of seatpost in frame; do that for 3 days, while inserting a hefty screwdriver into the holes drille earlier and trying to twist with all your might at least 5 times a day, and hammering the sides with a heavy steel hammer; next 3 days repeat ammonia application procedure but with frame turned right side up; be ready for it to give. it sounds complicated but it is guaranteed to work. if it doesn't it may take a little longer and more applications. just be patient and when you rebuild, put PLENTY of grease or antiseize. same goes for cro-mo pedal axles on alloy crankarms, cro-mo BB spindles on alloy cranks, cro-mo bolts in alloy shifters, etc.
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Old 03-05-06, 09:41 PM
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Originally Posted by Dave87
Hello, I am new to this site and also new to fixing bicycles. About a few weeks ago I just purchased a Giant Rincon SE mountain bike at a flee market and planned on giving it a new paint job. I removed the wheels, handle bars, seat,and breaks from the bike but am having a bit of difficulty removing the seat post. I heard a couple of ideas such as applying ice and a cold wet rag arround the post to weaken it's bond, as well as the idea of putting the bike on a vice and applying ammonia to the post, both of them producing little results. Is their any other ways to remove a stubborn seat post? Your response would be greatly appreciated.
Here's Sheldon Brown's article on stuck seatposts:

https://www.sheldonbrown.com/stuck-seatposts.html
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Old 03-06-06, 06:38 AM
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Take the bike outside, lay it down and pour a pan of boiling water over the seat post. As aluminum expands more rapidly than steel this will initially make the seat post even tighter, but after allowing it to cool the expansion followed by contraction as it cools is often enough to break to seal.

This method has worked many times for me, and it will not harm the frame or the paint unlike applying other forms of heat. The problem is caused by corrosion started by moisture, and a chemical reaction sets in between the aluminum and the steel. It is almost as if the two become welded together. Aluminum seat posts and handlebar stems should be removed periodically and a smear of grease applied, especially if the bike has been ridden in the rain.
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Old 03-06-06, 06:43 AM
  #9  
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Have you tried yet a simple penitrating lubricant? Let it sit for 24 hours, then try it. It can work very well, and offer no potential damage to your bike. (Of course if you've tried that and it's not working then perhaps some of the other suggestions.)
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Old 03-06-06, 08:26 AM
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this all said, you might be dead in the water. Sometimes when an AL seatpost chemically bonds to a steel frame, there's nothing that you can do... just to throw this out there as a possibility.
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Old 03-06-06, 09:47 AM
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Originally Posted by timcupery
this all said, you might be dead in the water. Sometimes when an AL seatpost chemically bonds to a steel frame, there's nothing that you can do... just to throw this out there as a possibility.
As an absolute last resort when all else fails the seat post can be melted out, but this needs to be done by a framebuilder or someone who knows what they are doing. With the frame held in a vise upside down, the whole seat lug area has to be heated uniformly to a red heat and the aluminum seat post will melt and run out. Of course care must be taken not to go beyond the red heat to orange red or the brazing will melt. This is not advisable if the frame is silver soldered, and of course the paint job is destroyed so a repaint is necessary.

A word of warning when the aluminum melts it happens suddenly so keep your feet clear. Having your shoes filled with molten metal is no fun.
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