shutuppostman

First things first, ive tried everything I can short of the methods to be discussed below which does include vice grip and elbow grease but not caustic soda+water or just cutting up the tube itself as im saving that for the very last option.

So in the youtube video by user Rj The Bike Guy titled "Removing Stuck Aluminum Seatpost In Steel Bike Frame" (sorry for the no link, cant post links yet as a new user :/) this guy uses quite a few no no tactics (pipe wrench etc) but if research from threads here has taught me anything, its that he was at least right to employ amonia for breaking bonds and penetrating oil for obvious reasons. Again, its a somewhat unorthodox video (though I dont know what would be orthodox in this case) but there is value in it. So much so, ive decided to employ similar methods involving amonia and penetrating oil. That said, I have a few questions:

1) is my bottom bracket at risk? Obviously, taking it out would be the safest bet but that isnt an option so if i need to replace it, so be it. Thoughts?
2) how long should I be waiting between lubrication/amonia applications? Minutes? Hours? Days?
3) any order of those two things i should be following? Lube first amonia second or vice versa? Should i even be doing them at the same time/close to one another? What would your method be?
4) Though question number two may answer this, how long of a process am I looking at here? I dont know what the metric for the severity of the situation would be but it completely resisted any movement in a vice grip with two large men at it if that says anything. Tldr; its seized on possibly an aluminum/steel chemical bond level.
5) open discussion: what would your step by step process in this be?

Please note, i understand there may be better ways to do this and feel free to share them but as of now, this is the method im going with so please keep that in mind as you answer with, ideally, information pertainent to this method. Again though, no wrong answers!

Thanks in advance!

maddog34

my first idea..... i'd search "stuck seat post" on this forum.

you'll find DOZENS of posts to read through.

suggestions include : laser beams... dynamite... cutting torch... hitting the seatpost on all sides, with a hammer repeatedly, and soaking with penetrent in between smacking sessions... oh wait, that actually helps loosen the molecular entanglement that you're presently dealing with! and smacking it downward can help too... if your seat post isn't already all the way down, or you're dealing with a piece of water pipe that was too big to begin with, like i've extracted before... he drove it in with a sledge hammer, and was quite proud of his "accomplishment", too!

i'm dealing with a "suspension post" right now... it was already all the way down, and was left in the rain for @ 5 years... my bench vise crushed the post.... the spring, etc. was removed long ago... next is drilling it out as much as possible, then cutting grooves with a 1/4" burr and my porting tool.... i refuse to yield to the corrosion monster!

Steve B.

I once used a SawZall to get a post out.

I tried pretty much everything, excepting the big Coke bottle filled with dry ice wrapped around the seat tube, also known as cooling the separate metals so they contract at different rates, etc... Dry ice is a pain to deal with.

I cut the post off about an inch above the top of the seat tube. I then carefully and slowly cut the inside of the post till it was free to move.

I now am religious about removing posts and luring them.

3alarmer 

.
...one of the things that rarely gets mentioned here is using an adjustable reamer to start small, reaming the seatpost out from the hollow hole in it when you cut it off, and gradually expanding the reamer outward. You can buy an adjustable reamer that will work (of decent quality) for about fifty bucks. I think a handle that will go onto it is another 40 though....so unless you're doing this a lot it's probably not a good use of your money.

3alarmer 

...this is an interesting question. My own conviction is that ammonia only works well in this situation if you have not already started dumping oil in there. It needs to soak into the interface between post and seat tube, and any oil effectively prevents this from happening.

When I've used ammonia (I haven't for quite a while), I dumped it in from the bottom of the seat tube with the bike upside down. After a couple of days like that (stop up any holed that leak the ammonia), then penetrant (50/50 ix of ATF and acetone). Then the big bench vise on the post (or a scrap saddle in the post if you are trying to save the post) and twist the frame off the post. Works for me, mostly.

sch

Reamers are designed to remove ~0.001" or less per rotation so expect that approach to take awhile, but none of these
methods are fast and easy. Some seat posts have an oval interior where the reamer would not work. A friend spent
3 days (nights mostly) on a seatpost in a Burley tandem, finally getting it out with the lengthwise hack saw approach.

A Kalloy SP I autopsied (joint at top failed) had a tapered interior, thicker near the seat, thinner at the bottom end.

3alarmer 

...reaming aluminum goes faster than reaming steel. Possibly you already know this.

Oval seat posts are, indeed oval. The upside of this is they are less prone to collapse when grabbed in a vise.

fietsbob

Check the FAQ hundreds of posts on that, in the archives yet?