kinokokun

I bought a vintage Trek frame a few weeks ago only to find the seatpost severely stuck in the frame. The guys at the LBS put it in the table vise but it wouldn't budge. I finally got it out by soaking it in ammonia and then using a pipe wrench. Here's what I learned here and elsewhere about stuck seat posts:

* Pay attention to what metals you are working with. I figured my post was aluminum because a magnet did not stick (though apparently this is not a foolproof test). The LBS guys heated up my post which would actually cause it to expand (in a way this could still be good after the post cooled down, maybe?). Apparently with steel frame and aluminum post you want to cool everything and then heat the frame because the steel will expand faster than aluminum (saw that on a post here I believe). I eventually removed the seat post without using any heating or cooling.

* Sheldon is right that ammonia eats at the corrosion that forms between steel and aluminum. I turned the bike over and poured the ammonia (bought it at Kroger grocery for $1.99) into the seat tube from the bottom bracket area. I was able to fill up the whole seat tube until I could see from the BB hole that it was full (it leaked out very slowly if at all -- luckily my seat post was impermeable and I did not have to use any tape). I let it sit for about 48 hours, occasionally banging a bit with wood on the seat post and seat tube hoping to move things around a bit.

* Sheldon might be wrong when he says not to use a pipe wrench. A pipe wrench, I found out, is designed to tighten onto a round pipe as you pull. I was finally able to free my post by putting the pipe wrench on there, laying the bike over, and, using the ground as leverage against the end of the pipe wrench, standing on the whole thing so that the force of my weight downward turned the wrench.

* There's this place called Harbor Freight that has ridiculously cheap tools and other hardware store items (thanks to the LBS for this tip!). If there is one near you I would definitely check it out: https://www.harborfreight.com/cpi/ctaf/retail_stores.taf

* Word, thanks to everyone else who posted on stuck seat posts and helped me free mine!

Panthers007

The LBS might want you to shop at Harbor Fright (as I call it) as their tools are cheap and tend to break - or damage what you're working on. Then you'll need to take your bike back to the LBS for surgery.

Perhaps this may be a cynical point-of-view, but Harbor Fright tools, by and large, are garbage. There are a few exceptions though. My advice is to save up your money to by the BEST tools made for bicycles. Unlike Harbor Freight's offerings, you won't end up buying top-quality tools twice.

kinokokun

Yeah I think it depends a lot on what you are getting. I got some compartmentalized plastic storage cases for a couple of bucks, locktite $1.99, a big steel pipe wrench $7.99, a nice hammer $2.99, orange hand cleaner $1.99. I probably wouldn't go for their $14.99 drill, though.

kenhill3

LOL! I'll add the moniker: Horrible Fright.

I work as a carpenter and will never buy a crap tool there unless I plan to use it once then throw away. I do buy some consumables there like SDS masonry bits.

HF= Godawful crap. I've ended up hating the smell of cosmoline or whatever the hell it is hanging in the air there.

End of rant.

bikemeister

Appreciate that info about the ammonia, newbie!
Gotta love a forum like this - everybody can learn something!

dabac

No, but you're working from different premises. A pipe wrench is likely to gouge the post severely, even to the point of making it structurally inadvisable to reuse the freed post. it you have no intention of re-use, this concern of course goes right out the window.

... And can easily do so to the point where the post caves in on itself, which isn't a problem either if you see the post as sacrificial. If you've grasped the post right where it exits the frame, squashing it will turn the situation from bad to worse.

If it's a post with an integrated saddle clamp, grasp immediately below the clamp where the post is at its strongest.

Great care needs to be taken with that kind of brute force approach, you can bend a frame/drop outs that way.

Anyhow, congrats on getting it out.

dwood

[QUOTE=Apparently with steel frame and aluminum post you want to cool everything and then heat the frame because the steel will expand faster than aluminum (saw that on a post here I believe).QUOTE]

The coefficient of expansion of aluminum is greater than steel, so the aluminum post will expand faster than the steel frame. Using heat with an aluminum/steel problem is usually a bad idea.

DON

AndrewP

Unless the steel is on the inside - like pedals stuck in crank arms. Boiling water is not hot enough to damage a crank arm, but will cause enough expansion.

brianbarber

I hesitate to resurrect dead threads, but this is one of the ones I read when trying to extract an extremely stuck seatpost. I had to resort to sawing it out. Here is my success story: The Experimental Runner: The Straight Goods on Removing a Stuck Seatpost. Thanks, everyone! Let the build begin...

le mans

i used the same procedure for a steel seatpost stuck in a steel frame, except i soaked it with vinegar with success. gripped the bottom of the seatpost with a large pipe wrench.. got it out.. which left a few marks but it didn't matter.. it was positioned pretty high for my liking and is reusable.
i have another one coming up but its an alloy seatpost stuck in a steel frame, it isn't set too high and i want to reuse it for the bike. should be a challenge.

Jimsl78

Sweet victory comes to those who refuse to give up.
Most people wouldn't go through all the trouble and they don't understand, but you made it your mission to save that frame from becoming trash!
Bravo!

lopek77

Canker

I used the lye method on my surly. I tried cutting out the seatpost but didn't have the patients for that crap. Then I tried using an adjustable reamer which worked pretty well but I couldn't get it deep enough into the bike frame to get all the seat post. After I reamed a lot of the post out I tried jamming things like screwdrivers down between the frame and seatpost hoping to break it free but all that did was totally mangle what was left of the seat post. Then I finally decided to go with lye because I had nothing left to loose. Wish I had just done that from the start. Had what was left of the set post dissolved in a day or two with very little effort on my part. Just had to go out and refresh the solution every so many hours. You don't have to go to the extreme hazmat setup they used but you do need to be carefull.

Reynolds 

Brute rotating force can tear open a thin wall seat tube (I saw this happen - not to me).

squirtdad

that is not true since that is exactly what you have done with 3 out of your 4 total post.

Just post and quit reviving threads

brianbarber

Will do, squirtdad. I'm normally a good little poster, but I saw a different collection of posters on each thread and wanted to let all of them know how much they helped. Thanks for your input, too. I suppose I let my enthusiasm get the best of me.