Removing a stuck seat post

[Sailingjab1976]

Hi,

I've found lots of advise on removing a alloy post from a steel frame, but how do you remove a steel post from an alloy frame?

I've got it soaking with penetrating oil, but not budged at all yet.

Any advice welcome, as don't want to scrap a '91 Zaskar.

Thanks

 

[SEANSTEPHENS]

Re:

Ive put a couple tips on your post in readers bikes

Sean

 

[02gf74]

There is a chemical that wil disolve steel but leave the aluminium alone, forget what that is right now....

Nitric acid will disolve the steel and anodise the aluminium, that may result in a colour change. Or alum solution.

Have you tried heating, eg boiling water, al expands more than steel so should loosen its grip.

 

[integerspin]

There is a chemical that wil disolve steel but leave the aluminium alone, forget what that is right now....

Alum?

 

[bwhsh8r]

I bought a Ti Airborne to resell that as it turned out had a VERY chemically seized aluminum post in it. I used my grandpa's bench vice on the seat post head along with the frame for leverage, and I just kept jiggling it until it finally started to twist slightly.

After a TON of work it eventually barely came out.... along with some weird chemical reaction byproduct.... don't over do it though, since once you break the post you just created even more work for yourself.... fortunately the one jammed in that frame was a cheap icon one that was quite thick

I figure that strategy should work for just about anything.

 

[hamster]

Use a search on this site, there are loads of threads on freeing stuck seatposts.

 

[Sailingjab1976]

Re:

There are loads of posts in RB and other sites, but they all seem to relate to a steel frame and either an Alu or steel post. This is the other way around - A Zaskar frame and a steel post that has previously been chopped down.

 

[hamster]

Heat is going to be the way. However you are fortunate in that a steel post will take drilling and a tommy bar through the end to twist it. Running Plus Gas regularly for a week into an inverted frame via the BB works wonders.
However I think sawing out the post from inside (a last resort in Alu posts) is just about impossibly long to do.

 

[peacefrog]

If you don't want to save the seat post and just get the damn thing out. i have the perfect solution. Never failed me. Take a air hammer like pictured below with a attachment of course; i like this one in the picture below. Your free to chose whatever attachment you want. Find a nice place to put the chisel, and air hammer that Mofo right out of the frame. Upwards of course you don't want to hammer it back in the frame...I put that in there because someone actually asked me which way to hammer it. Stand up the frame out it out in the yard or on carpet, probably don't want to do it on the concrete or on your foot. Whatever is comfortable and have a go at it.

 

[SEANSTEPHENS]

Re:

If you apply heat it will discolour the aluminium badly and youll ruin the appearance of the frame, also theres still not enough post to grip onto to pull it out even if the post does loosen up. Also with the chisel idea, again theres not enough post showing out of the top of the frame to get any grip on so i dont see that working either.

Can i also point out that when its heated up and left to cool down then aluminium weakens and is more prone to cracking