The Dreaded Stuck Seat Post
09-15-20, 11:18 AM
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The Dreaded Stuck Seat Post
As the title suggests, I have an aluminum seat post stuck inside a steel frame. I've tried putting PB blaster on it from the topside and from the bottom. I tried using an 18 inch pipe wrench to no avail, and it's now been over a week since I first started trying to un-stick the post from the bike frame. I have no interest in trying any of RJ's shenanigans; I am ready to skip to the end of this process. I have a hacksaw I can use to cut the seat post, but then what? If I cut the post, there will still be a hollow aluminum cylinder stuck inside my bike frame; how do I get it out then?
this is a FAQ posted many times..
09-15-20, 11:49 AM
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Trouble with PB blaster is when there's simply no space for it to even get into the affected area. Ideally you would be able to soak the entire seat tube in PB, but that's pretty difficult.
You could try this: If you have enough seat post exposed, try to knock the post (with a 5 lb sledge on a wood block and the frame resting on wood or some sort of padding softer than concrete) deeper into the frame. The idea being that you might break the bond between the post and the tube. Heat and cold sometimes help, but you could really damage the paint and just find yourself more frustrated.
You could try this: If you have enough seat post exposed, try to knock the post (with a 5 lb sledge on a wood block and the frame resting on wood or some sort of padding softer than concrete) deeper into the frame. The idea being that you might break the bond between the post and the tube. Heat and cold sometimes help, but you could really damage the paint and just find yourself more frustrated.
09-15-20, 11:52 AM
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Yeah, that's not going to happen. If my only options are "leave it stuck in place forever" or "dissolve the aluminum from the steel," then I'll just leave it stuck in place. I don't have the appropriate space nor do I have the necessary PPE for dealing with high-pH, caustic solutions in my apartment. All I wanted to do was lower my saddle by 0.5-1.0 cm because I got some new pedals, but it sounds like the path of least resistance is to return the new pedals and leave the saddle where it is forever. Done and done.
09-15-20, 11:56 AM
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Trouble with PB blaster is when there's simply no space for it to even get into the affected area. Ideally you would be able to soak the entire seat tube in PB, but that's pretty difficult.
You could try this: If you have enough seat post exposed, try to knock the post (with a 5 lb sledge on a wood block and the frame resting on wood or some sort of padding softer than concrete) deeper into the frame. The idea being that you might break the bond between the post and the tube. Heat and cold sometimes help, but you could really damage the paint and just find yourself more frustrated.
You could try this: If you have enough seat post exposed, try to knock the post (with a 5 lb sledge on a wood block and the frame resting on wood or some sort of padding softer than concrete) deeper into the frame. The idea being that you might break the bond between the post and the tube. Heat and cold sometimes help, but you could really damage the paint and just find yourself more frustrated.
09-15-20, 11:56 AM
#7
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To Get the rest out of the frame..
Hack saw blade out of the saw-frame, laboriously cut into the seat post tubing, to get it out in slices..
09-15-20, 01:33 PM
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Cheap method with some success it to turn bottom bracketless frame upside down and pour enough icewater down seat tube to fill up the seatpost. Let sit for at least 15 mins. and change to fresh icewater once or twice during the process. Have a gallon or so of boiling water ready. Empty out icewater and slowly pour boiling water over the seat tube area surrounding the seatpost. After all the boiling water is used quickly try to twist the seatpost loose with your pipewrench again. Works sometimes and hey, it doesn't cost anything to try.
09-15-20, 02:42 PM
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You slot the post in a number of spots and need to get a prying tool to peel them away from the seat tube so the post comes out in pieces. .
09-15-20, 02:58 PM
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I'm with surfer on this. I poured in the mix (about 6oz.) and let it sit overnight. I figured I would need enough of the solution to fill the inside of the post and then lap over into the seat tube to get full penetration. Then I used a crescent wrench on the flats of the post, and got out my three foot persuader. Using the top tube and the persuader against each other for leverage. Mine broke free on the first attempt. Be sure to keep the frame upside down during the procedure to allow even more of the juice to work into the space between the post and frame. Then drain the solution out over an oil drip pan to catch the mixture. HTH, MH
Last edited by Mad Honk; 09-15-20 at 03:03 PM.
09-15-20, 03:22 PM
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Crush the old seat post into a well secured large bench vise (bike upside-down) and use the frame as leverage to free the post from the tube, heat will help as well as several days of soaking with PB blasterbefore attempting extraction
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