Stuck seat post

[Hendo]

The seat post in my MBK is stuck fast!
It's a steel post and aluminium frame, and I've heard that they can be unwelded by the introduction of household ammonia into the seat post tube and leaving it in there to work it's magic!
But...... Does anyone have a good description of the technique used to archive this?

 

[MrWill]

Get a long lever on top of the post and twist.

 

[KneesUp]

I know you can dissolve an aluminium post stuck in a steel frame with caustic soda. I'm guessing you want to keep the frame though.

 

[Hendo]

Yep, I'd like to keep the frame. Is it the aluminium that gets dissolved?

 

[derrick]

Stick seat post in a vice and twist frame, make sure vice is well bolted down.

 

[KneesUp]

I'm afraid so

 

[Lanzecki]

http://en.wikipedia.org/wiki/Galvanic_corrosion

Soak it in wd-40 or better for a long time. Stick it in a good vice (expect to destroy the post) and using the frame as a lever twist back and forth.

Using the Hot Alum trick will work, but that amount of steel could take days.

Learn the lesson : Grease.

 

[Gravity Aided]

Hot vinegar may work as well, dissolving the corrosion that has stuck the seatpost. I saw that work once. I was successful once using penetrating oil, but that may be dangerous stuff

 

[sittingbull]

You need to remove the bottom bracket, turn the bike upside down and support it, ideally in a bike stand, pour your releasing agent of choice into the BB opening, down the seat tube having first plugged/sealed around the saddle end of the post. Leave it for several days, maybe even a week, then try to remove the post.

Ammonia, vinegar, Plusgas and Cola amongst others might do the trick. Instead of removing the BB you might get away with squirting the Cola etc. through the bottle cage mounts using a washing up bottle. If this soaking method fails you'll have to get physical with heat or a vice or hacksaw.

Fortunately I've never had to do this so cannot speak from experience, but there's plenty of information on the 'net if you do a search.

 

[mrbikerboy73]

Stick seat post in a vice and twist frame, make sure vice is well bolted down.

I remember doing this to a mates BMX when I was a kid. It worked when nothing else would!

 

[PatrickPending]

Sheldon to the rescue....

http://www.sheldonbrown.com/stuck-seatposts.html