Stuck seat post.....

[Steve Shindig]

So I have a painted alu pivotal post stuck in a normal 4130 frame.  It went in fine and then got stuck and I can't shift it.  Any ideas how to get this thing out please?  Thanks.

[CD17]

I had this a few weeks ago on a 85 Performer, I soaked it every day with WD40 & it still would not move 

In the end I put the seat post in the vice & turned the frame, it came out 

& it did not fook the seat post 

[motomagII]

buy some rust remover liquid water it down soak in it for short while .i did this and after ten mins it just slid straight out easiest stuck post ive ever got out .works a treat

[ORB]

Hmmm, alloy and 4130

Rust remove wont do much as alloy does not rust!

I would plug up the hole in the bottom of the seat tube (inside the BB) and fill with Caustic Soda.


The caustic soda will eat away at the alloy. Do NOT breathe the fumes!

[Steve Shindig]

Cool,. thanks for advise dudes, I'll try this caustic soda idea... this sounds like a good plan as I don't have a vice.

Cheers again. I'll let you know how I get on. So, Halfords for this caustic soda stuff?

[Swivel]

B & Q mate or any homewhere store, Halfords won't do it I think. B & Q best bet

[electro808]

I did not come up with this method but I know it works, if you don't have a vise...  Get an old stem, clamp it to the post then use a set of forks or some tubing (scaffy bar ) for extra leverage and use that to turn out the post.  You might have to lay the frame down and stand on it until you get the post moving. 

Try that before you start messing around with caustic soda.  Naughty, naughty stuff if you've got kids or pets knocking around...

[toys19]

Caustic soda sounds like a good way to ruin your frame, if any leaks out you will need to neutralise it. Otherwise it will leach into the tiny pores around the welds and make your frame rust to hell! Avoid.
The stem idea sounds sensible or I did this with an alloy uni post in my curtis frame -  hacksaw it off, then get the hacksaw blade or a dremel and cut a slot into the inside of the seat post so that you can jam a big screwdriver in and get the thing moving.

[Swivel]

Diesel, soak it for a while, then heat up up the frame and get it in a vice. We did this with one of my Gt Pro Performers and all was good 

[motomagII]

im telling you rust remover i used it on alloy frame with metal seat post stuck and it literally fell out once soaked in the remover

[TwoBobRob]

Whilst ally doesn't rust as such, it does corrode and ally and steel will mate if left in the right conditions....  In my job we have to isolate those two materials from each other.

I too would swerve the caustic soda until its last chance time.  Also, heat is unlikely to work as the ally post will expand quicker than the steel frame.

I assume the post is scrap?  If so, then I'd do as the others have said and repeatedly soak the post/frame area then after a few days I'd give the post a bloody good whack with a hammer straight down to try and get it to move. If it moves down, then you'll be able to get it going side to side, and then eventually it'll come out.

If all that fails, I'd cut if off flush with the frame and drill it out