Removing stuck or seized seatpost?

@SlimCharles can I ask what your sticking the hacksaw blade too to get it into the seatpost?

MY croix de fer has a well and truly stuck seatpost (previous owner mistreated it) and it's ever so marginally too low.

I had a mini hacksaw (the type where the blade projects beyond the handle) with a long blade. Once I’d made the initial notch with the hacksaw I then reverted to using the blade on its own, using a rag wrapped around the end of it to protect my fingers although this was super slow going. Haven’t had the chance to go back sawing since so its still not quite made my way through. I think I’m going to hit it with some WD40 for a few days once I’ve fully made it through the seatpost. Not sure what the plan is at this point for extraction though. Also, this rockhopper cost me 40 quid so if this goes wrong it’s annoying but not the end of the world. Best of luck!

I recently got a alloy seatpost out of a steel frame using caustic soda. It corrodes the aluminium but not the steel. It does damage the paintwork but if ur careful (keep it on the inside of the frame) there will be no damage.

I'm toying with doing this too. Living in an apartment at present though, and fancy getting my deposit back. New house (so long as the bank gives me money) needs a tonne of work so I can wait til I'm there to try that or the saw method.

Have you tried the threaded-rod-and-washers-DIY-seatpost-puller?

Had to do this stuck seatpost malarkey a couple times lately but it’s been successful without damaging the frame.

The other week I had a stuck stem, drilled a big hole through the middle and sliced some slots in the edges with an electric saw, stopping before it broke through to the steel and chiselled them out with an old screwdriver. Took ages and was a massive pain but got it done. Only thing I would say is if you use an electric saw is that it can hammer the remaining part further down so leave an edge if you can do that doesn’t happen. I cut it flush to the top of the steerer which was a mistake in retrospect.

Yesterday I had a seatpost stuck with about 3” in the frame. 1” diameter post which is 25.4mm.

Used a 25mm drill bit to drill it out. It was stuck hard to the very end, see the pics below for before and after. Had to keep it dead straight so it didn’t cut in to the frame.

This also took ages, about hour and half.
With the stem I drilled a 16mm hole straight through with no issues. With the seatpost it was getting very hot very quickly and heating the drill up very fast. Presumably due to the bigger size. Had to use lots of cutting oil and water on the frame to keep it cool and cut with the drill in a few half second bursts pulling out the drill to get the dwarf out and spray oil in. It got the seat post out and since it was so far extended out of the frame there was about 12” of remaining seat post left to use.

If I was to do again I would wrap a wet towel around the frame to help with drawing the heat out.

Big drill bits can be bought from toolstation for under a tenner and use on a regular drill chuck.

Use a low speed low torque setting as the drill can bind up quite easily. Use lots of oil to help cutting and keeping heat down.

Both of these were pretty much welded in the frame so very much a last resort.

Hope that’s some help.

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I recently picked up a bike for my partner and unfortunately it arrived with a seized seatpost. It is an aluminium post in an aluminium frame. It is possible to rotate the seatpost round using the saddle for leverage but impossible to get the post to move upwards at all. So far I have been soaking it in WD40, as I am under the impression that plus gas won't work if it is alloy on alloy... would coke make any difference? Is there currently a seat post seize expert on this forum able to help?

@ghostface I think if you've got it moving it should come out however being able to hold the seatpost or frame securely enough and twist is tricky.

Cheers @TheShipwright- thanks for the advice. The tubing is 7020 oria, I don't have my calipers to measure but I wonder if it might be a 27.2 seatpost forced into a 27 seattube. I've read conflicting things on the internet about the seat tube internal dims of 7020 tubing. There is no discernible ripple in the seattube but suspect if it was only .2 of a mm this wouldn't be so obvious. My partner already took it to a bike shop who put it in a vice as I don't have access to a vice - and they said it was so tight that it was causing the worksurface to lift. They quoted £100, but as an unknown entity due to not knowing how long it might take. Nightmare

Does PBlaster work on aluminium on aluminium or not? Or would another penetrating oil be better?

Just spoken to The Seatpost Man who was full of helpful advice. Will follow his advice and see what happens soaking for the next week. He told me his is now up to 1500+ successful removals!

@ghostface it think it unlikely that a 27.2 post would go into a 27 tube, its much more likely stuck via neglect.
What did the seatpost suggest to try?

I've got one of these to do: alloy post stuck in carbon frame. not looking forward to it

in the meantime, I was just replacing the seatpost on my good (steel) bike and putting in a carbon post instead of alloy. I noticed however that there seems to be a gouge or dent in the seat post almost as if it has been impacted (maybe when we moved house? it's been in a box for a while). should I worry about this and could it be repaired? I'll try post some pics

edit: on closer inspection looks like there is some delamination so probably not worth the risk of riding. not sure if these can be easily repaired : /

OK... back to trying to get the alloy post out the carbon frame...

attempt 1. lots of GT85 around the collar, twisting from the saddle. nothing. FAIL
attempt 2. turn frame upside down and spritz about a third of a can of RP-90 into the seat tube. leave for an hour and a half. try to twist with the saddle. FAIL
attempt 3. pour another batch of RP-90 into the seat tube and leave over night. currently in progress, will report back

in the meantime, I've also ordered some finish line chill zone - in the anticipation that attempt 3 will fail and I'll have to try the thermal contraction method. I might try to find a jab saw and a big pipe wrench too (would 14" be big enough?) wish me luck

this is ostensibly my turbo bike now so not the end of the world if it doesn't come out but it's still a half decent frame (original 2005 focus cayo) so would be nice to be able to ride it outside now and again

attempt 3. fail. not moving at all. on the plus side, when I tipped the bike back the rightway up, significantly less RP-90 came out the hole on the underside of the bike. so I assume that means it has soaked in (unless it evaporates...)

for attempt 4, I think I'll give it another overnight soak in RP-90. might as well exhaust this can of juice while I wait for the chill zone to turn up.

anyone know if plus gas is better/worse/equal to RP-90?

attempt 4. naw. chill zone it is. not holding out much hope. old man was on the look out for a bike, might gift him this one and let his (retired) self have a go at this

have you tried a slide hammer? that style of removal seems to be the way. I don't even bother trying now unless its really worth it.

had never even heard of a slide hammer. not sure where I'd get access to one of those. car garage maybe?

Can buy them easily enough. There’s a guy on YouTube who had success using one.

Ok so I have now two bikes with totally fused seatposts those slide hammer vids look quite persuasive but decent ones are expensive, wonder who uses these things no hire places near me is it a car mechanic thing?

Yeah they use them for getting things like stuck drive shafts and things that need pulling out with a bit of wallop.

I have been on the look out for a heavy one, you’re right they are expensive although you could make one. It’s just a rod with a weight.

There are videos where people have made a frame that pulls the post out, they look pretty good and fairly simple to build if you have some suitable scrap steel floating around.

Ah ok, I might ask at my local car garage then, I have a mate who also says he might try and make one, beats trying to dissolve it I suppose..

I think I give up on my focus

I started pulling the parts off to transfer to my current project and there was some nasty looking chipping/delamination hidden at the BB shell behind the crank arms. doesn't look fatal but not sure I can be bothered persevering with the seatpost now I have a new frame. not sure what the servicable life of a carbon frame is supposed to be but I got a good 10 years out the bike so I'm happy.

I have a slide hammer & 36" Stillson wrench in SE1 if anyone would like to come over and use them.

I bent a 12mm steel bar running through a seatpost this evening.

I think I may have to cut this seatpost out. What bullshit :]

The Seatpost Man was amazing, if you can face the £69 charge and posting the frame, I couldn't recommend him enough. I had a frame and was trying everything to get the post out, eventually it came to how much time I was spending and money I was spending on things like plusgas that weren't making any difference. I posted it to him and had it back in a few days. I think if it is a frame you care about enough, then his charge is totally worth it.