[DubDom]

Hi All

Anyone have any wisdom on how to remove an alloy seat post that is stuck in a steel frame?

[tomtom]

Try marinating in WD40 for 24 hours (or keep squirting some down every couple of hours)... if that doesnt work, then (sorry this may hurt your paint job) a blow torch on the frame to warm it up a bit and the odd whack with a hammer might do it...

If you can get it to budge a little (even twist a couple of MM) then with some WD40 you can eventually get it to free up...

[runt]

If you have access to a vice and haven't tried this already.....

Saddle off, frame upside down, clamp top of seat tube in vice, turn frame.

The extra leverage shifts most posts, depending on the design of the top of the post, and how easy to clamp.

[fatdoc]

 

With both of the above...

[Bubba]

Might be worth trying some proper penetrating/dismantling oil before being the blowtorch out.

[Palomides]

I managed to get a rather lovely Campagnolo Record seatpost out of a rather lovely steel Bianchi (that one of my colleagues was about to take to the dump!).

He'd already broken one saddle in a vice, so I left the frame upside down overnight with a can of coke inside the seat tube - this was injected into the frame via the bottle cage boltholes as I didn't have the correct bottom bracket tool.

A few minutes of heatgun and twisting got it out after that.

Last resort is apparently to cut the top off the seatpost then very carefully cut through the remaining stuck bit with a hacksaw blade until it can be collapsed and pulled out...

Edit - this one. If you look closely you can see the line on the seatpost where it was stuck.

[DubDom]

Thanks folks

the coke suggestion sounds interesting. I have had a bit if a google too, of course and I've got a cheap can of plus gas on its way to me, so fingers crossed. In the absence of a vice, any thoughts, or does someone have the use of a vice in the Sheffield area?

cheers

[johnx2]

My local bikeshop snapped my fuel x8 seat post off in the frame when two enthusiastic but gormless lads tried the upsidedown in a vice technique... Then had ample time to reflect on the error of their ways when going at it with a hacksaw.

[Sam]

steel Bianchi (that one of my colleagues was about to take to the dump!).

some people are absolute morons 

anyway, if the post is beyond soaking in solvent/plus gas/coke etc. and it can be sacrificed you can: cut the post near to the top of seat tube and taking a hacksaw blade, cut slots down the length to cut the stuck tube into half or quarters etc. Saves twisting the frame.

[northerngreg]

Dissolve the post out with caustic soda - it eats aluminium but leaves steel untouched:

http://sheldonbrown.com/stuck-seatposts.html#carbon

[twoshoes]

I don't think heat will work - pretty sure that aluminium expands faster than steel. Try cooling it somehow?

You might not have much luck with penetrating oil either. Three out of three stuck alloy posts in steel frames I've seen have been due to the post corroding/oxidising/whatever it is they do. Coke (maybe?) or, as above, caustic soda might work.

I'd try both heat and penetrating oil etc, but wouldn't try for too long and would jump to:

Twisting the frame can definitely work, but you can also write off both the frame and seatpost this way. I wish I didn't know this for a fact... Be careful which bits of the frame you twist with and watch out for the frame flexing and potentially cracking near the top of the seattube/clamp slot.

Sawing the post out with a hacksaw blade works. Takes a while, but works.

If you don't care too much about the frame, I've also seen someone drill a hole through the BB shell and use a rod to hammer a stuck post out before putting a blob of weld in the hole. Still rides fine.

[tomtom]

Having freed many corroded parts (Steel-steel & ally-steel) on old motors with heat - its not so much the heat causing differential expansion, more that it seems to weaken the stick created by the corrosion...

But the Coke method sounds like a great starting point.. Caustic soda would be an effective but very very messy way I suspect!

[DubDom]

My neighbour is a retired gas fitter and he has recommended hot vinegar instead of coke, which is interesting...
hmmm, I might not rush to do the caustic soda plan.