Forum: bicycles.stackexchange.com
Tags: <frames><seatpost><rust>
Title: Removing Seat Post rusted into downtube
Question: I have an old steel frame (Columbus Number 2 I think) that has the seat post (Suntour Superbe Pro - see, I said it was old!) rusted in. I have tried lots of WD-40 but it will not budge. Any tips on how I can get it out without having to cut the frame up?

Answers:
sents: text: Before you take any more forceful measures, it may be a good idea to think a little about chemistry: 'Rust' is typically the name put on any type of corrosion, but technically & specifically, it is the corrosion of iron (or steel) to form iron-oxides.
text: Although your bicycle is most definitely steel, your seatpost is not -- it's aluminum-alloy, which does not 'rust', but definitely corrodes (creating aluminum oxide).
text: WD-40 is a penetrating oil which is designed to, amongst other things, break up iron-oxides.
text: However, it is pretty much useless against aluminum-oxides, especially when they have already corroded & bonded.
text: Ammonia, however, is spectacularly good at eliminating aluminum-oxides.
text: Therefore, if WD-40 isn't doing the trick, get some ammonia, apply it in a similar fashion, and let it sit.
text: It may just be all you need!
answer_details: author: bicycles.stackexchange.com/users/23/Dustin Ingram
score: 20
sents: text: This is a tough one.
text: It's not impossible
text: but you really need mechanical advantage.
text: If you can clamp the seatpost, you will get the best chance at freeing this.
text: You will probably damage/lose the seatpost with this method.
text: Make sure the seatpost is free ofgrease and oil on the outside.
text: Turn the frame upside down and clampthe seatpost into a bench vise.
text: Spray
text: WD-40 into the seattube fromthe bottom bracket opening.
text: It will probably be dripping rusty coloredoil out the top of the seat tube (which is now facing the floor - you might want to put something to catch the oil under there.).
text: Carefully hold the head tube and therear stays and try to rotate theframe on the post.
text: Work
text: it slowly and carefully beingsure not to bend the stays!
text: * Make sure the seat post is notrotating in the vise (if so, clamptighter)
text: This process can take some time.
text: You will need patience and lots of WD-40.
text: Eventually, the post will rotate in the seat tube and you will be able to work it out.
text: *
text: The trick is knowing how much force to apply.
text: Sometimes you need more than you think and sometimes you apply more than you need (which results in unwanted damage).
text: This difference comes with experience.
text: Oh
text: and also: grease the new seatpost well before you put it back in
text: - you'll appreciate it later.
answer_details: author: bicycles.stackexchange.com/users/87/42-17
score: 10
sents: text: You should check out the 15 Way To Unstick a Seatpost by Sheldon "Unggggghhh!"
text: Brown http://www.sheldonbrown.com/stuck-seatposts.html
answer_details: author: bicycles.stackexchange.com/users/1493/Aleksandr Levchuk
score: 8
sents: text: Untested and at-your-own-risk, but this is what I would try: Soak the rusted join with WD-40 from above and below (ie.
text: flip the frame and spray down the seat tube).
text: Let it sit for a few hours or overnight.
text: Secure the frame against something solid, like a heavy workbench (not a repair stand!).
text: Put an old saddle you don't care much about on the seat post.
text: Hit the side of the saddle's nose with a hammer or mallet.
text: Use short, hard taps -- using wild swings you're liable to hurt yourself or the frame.
text: The idea is to use the torque of the saddle to break the bond between the post and the frame.
text: You don't need to move the post much.
text: If the post moves, then you should be able to work it loose without the hammer.
text: If it doesn't, then worst case you've destroyed an old saddle.
answer_details: author: bicycles.stackexchange.com/users/157/darkcanuck
score: 5
sents: text: Cut the top off of the tube then carefully use a hacksaw blade inside the seat post to cut toward the seat tube.
text: A handle for a hacksaw blade works or just wrap the plain blade with a bit of tape to make a handle.
text: You should then be able to free the old seat post.
text: Or does the seat post extend way down into the frame?
text: Even then this should help as the WD-40 will get a better chance to reach the lower parts.
answer_details: author: bicycles.stackexchange.com/users/112/John Dyer
score: 3
sents: text: At the non-profit workshop, where I volunteer, we sometimes ream out the old Seatpost enough to stick in another, smaller-diameter Seatpost.
text: Especially if you don't care too much about aestetics and the seized seatpost reaches deep into the frame(at least 8-10cm, preferably more) this might be a viable option to just make the bike rideable again.
text: If it is less, you might be able to saw a slice out of the old seatpost(would have to be all the way into the downtube of the frame) and the crush the compromised tube with vise-grips.
text: In my experience, seized seatpost and their removability often boil down to how much effort and time one is willing to invest.
answer_details: author: bicycles.stackexchange.com/users/39007/MTTI
score: 3
sents: text: I had this problem with a very stubborn seat post (turns out there was a wedge in it to keep the post in).
text: One thing that I tried was putting a blow torch on the frame to try and expand it a bit to get the post out and loosen any corrosion.
text: I would only try this after WD40 has failed.
text: Disclaimer: this may damage your bike
answer_details: author: bicycles.stackexchange.com/users/134/sixtyfootersdude
score: 2
sents: text: there is aerosol spray available at most hardware stores called PB Blaster
text: it is much more effective when dealing with rust than WD=40
answer_details: author: bicycles.stackexchange.com/users/2192/mikes
score: 1
sents: text: Try put your seatpost / saddle on the vise ( reverse the bike ) then rotate the frame for pulling out the seatpost, put WD-40 or other lubricant for before you do it....
answer_details: author: bicycles.stackexchange.com/users/3189/Rick Ant
score: 0

Summary of the answers:
To remove a rusted seat post use WD-40 or ammonia and leave to sit. Then clamp the seat post and rotate the fame to pull out the rusted seat post.
It would be a good idea to start with applying a lubricant, such as WD-40, or ammonia if that fails. To remove the seat, you could try turning the bike upside down, clamping the post and rotating it. Moreover, consider using a blade within the seat post to free the way towards the tube. It is also possible to insert a smaller seat post in the old one. Finally, you could try using a blow torch to expand the frame and subsequently remove the post