[Closed] Stuck seat post

In a steel frame I'd go for the caustic soda approach.

It looks much more fun 🙂

I'm at the point where its the soda or hacksaw method, nothing else has worked.

Just wondering if anyone has done the hacksaw way. How far down do I cut the slit?

Right, tried the hacksaw method with no joy. When I try to bend the post in on itself it just snaps small pieces off.

Its been sat for days with coke in the seat tube and is not budged at all.

So... Where would one buy caustic soda ?

B&Q, big supermarket.

Give yourself a few hours and hacksaw it in half lengthways. It's time consuming but works well. Done it's several times.

I used a drywall saw to get an alloy post out of a Bonty Privateer. It worked well as the posts are pretty soft and it had a nice rubber guarded handed so you go at it like a maniac without risk of too much injury! Take the time to cut some decent notches and then use locking pliers to peel the remains away like a big alloy quaver, assuming you've left enough to grab onto.

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I bought an old '95 Kona Cindercone that had a stuck post, no amount of brute force would shift it. I turned the frame upside down, filled through the bottle bosses, the seat tube with penetrating oil an left it for a week. Still wouldn't budge! I then heated the seat tube with a hot air gun (hair drier may work) gave it a twist and the got covered in oil - seat post in hand!

Try putting the post in a big vice and turning the frame. Has worked on a few bikes in the past.

Drill a hole through the seatpost & get a long hex key/screwdriver/ something & put it through & twist it side to side. Worked for me & done it for a friend. The extra leverage from the long lever should do it. 🙂

Plusgas, a couple of mates and a very large spanner got my stuck dropper out (steel frame).

I had a similar problem a few years ago, alloy frame and seat post. Ended up using the cutting with hacksaw method but had to do 4 cuts down the full length of the post then got an old chisel to carefully separate the frame and each section of post. Found that the one cut method and taking it out like a bushing didn't work, nor did 2 cuts.

It took about 6hrs in total and was a bitch of a job, especially cutting evenly down the post and through it all - and making sure it was only post I was cutting. It won't happen again. On the plus side the bike still gets ridden regularly so it was worth the effort.

Right. .. the ****ers still in there. Tried the coke and the caustic to no avail. Cut the post short and downwards length ways as far as I could, when I try and bend the post inwards bits just snap off. Now left with not much post showing and its stuck tight. Its my favourite ride and I miss it. What sort of firm could attack this for me ? Happy to throw money at this or if anyone near reading or Basingstoke knows of a way and is happy to try there's a vast amount of booze in it for you. ...

The way I've done it with caustic soda is to cut lengthways down the post, but making 2 or 3 cuts going gently with a fine hacksaw blade. Keep listening for the sound to change when you reach the steel.
Then plug the ends of the seat tube, bottle cage bosses, etc and fill it with strong caustic. It'll get very hot (paint blistered on mine) and the three segments of post you've left will shrink enough to pull out easily.

Failing that a machine shop might be able to ream it out for you.

My favourite method is to go back in time, and put some grease on 😀

If you've got one cut, then try another at 90ish degrees to that, and then chisel in the smaller portion. It'll be easier to remove the last 3/4 then

Make 2 more cuts in the tube, it'll then effectively be in 3 pieces, place a small flat blade screwdriver between the showing section of the post and the frame and hammer it downwards until you break the crevice corrosion that's binding it. Repeat for each section.

Is this just not an excuse for a new frame/build?

Write it off and buy a new frame...Everyone loves a new frame! 8)

I genuinely wish I lived closer to the OP, I love fixing things like this!

This happened to me and a cromo frame with an alloy post way back when. Tried brute force and caustic and more brute force, then heat from a heatgun and even more brute force. I then resorted to the 4 hacksaw cuts and peel method but bits just snapped off and what was left would not budge with hammer blows on an old screwdriver. With subsequent experience of other stuck components over two decades I wish I kept on with more heat shocking - maybe I had weak caustic too. You have probably gathered now that 4 cuts and peel is a last resort. I think a decent shop or frame builder should be able to drill it out and then ream it clean. Good luck.