Removing stuck or seized seatpost?

and it's still firmly stuck in the seat tube, there was no way to move it even an inch with heat, wd40, hammering etc
Any other extreme ways ? i'm considering filing one side down for a few hours but how do i get it out of the tube if there's nothing to clasp ?

Have you tried caustic soda? Any pics?

This isn't your Fixie Inc, right?

caustic soda...

check the top of this page ^

i dont recomend this lightly, but it sounds like caustic soda may be your best option.

I personally don't like the sawing technique as it risks damaging the frame.

my technique was
a - remove cranks bottom bracket and this new seat post if possible.
b - plug top of seatpost with blu tack and a thick plastic bag around the blu tack.
c - suspend upside down bike in a workstand if you have one or some coat hangers
d- pour in a made up solution of caustic solutions ( its supposed to be more violent with warm water, but i did this in december when it was really cold) i used a funnel made out of an old coke bottle to make the pouring more accurrate.
e - at this point it fizzed out of the bottom bracket shell then settled down so make sure you pour in a little at a time.
f - wait 24 hours, or until it stops making a fizzing sound at which point i opened it up and checked progress.
g - if it's worked pull the scarred remnants out, if it hast got through enough then start again, it tooke me three days of this process.

my other advice is wear rubber gloves, and work in a well ventilated area (outside if you can)

good luck.

and it's still firmly stuck in the seat tube, there was no way to move it even an inch with heat, wd40, hammering etc
Any other extreme ways ? i'm considering filing one side down for a few hours but how do i get it out of the tube if there's nothing to clasp ?

dude, the heat will not work. u may try and live with it...there is a massive risk to damage the frame. Try pouring shave ice in the center of the tube... then try to hammer it with elastomer hammer head only...see what happens

My friendly LBS have tried the penetrating oil method to no avail, so tonight its hacksaw time while watching the Champions League match on TV as i dont fancy the heat method and i didnt like the seatpost anyway

I’ve made a brace (When I say made, I really mean super glued the blade to a to a strip of steel) to strengthen it slightly to try and stop the blade flexing when its inside the frame.

my other advice is wear rubber gloves, and work in a well ventilated area (outside if you can)

and goggles.

The caustic soda method is really the only guaranteed method of removing an alloy seatpost from a steel frame.

It will dissolve the seatpost entirely, given enough time, so yes, it is serious shit.

Remember kids, always wear goggles and get a grown-up to help.

"Fiiiiizz......"

Do I have to wait three days? I'm tempted to take a look at it now (18hrs or so) but it's a hassle sealing up the end of the tube. So I might just put some more caustic soda through the BB and try to think about something else.

I got a big mate and a fat long broom handle, stuck it through the saddle railings, I held the bike, he levered it. Took about 10 mins off beastly levering and bang!! It was free.

Fuck me that saddle is strong, Specialized one for about £60.

I tried other stuff to no avail, so this was a last resort.

I have a powdercoated alu seatpost jammed into my steel frame. the extra width from the paint means it's well and truly stuck. not tried anything other than brute strength yet, screwdriver etc. really don't want to damage paint/frame so caustic soda method beckons. well excitin.

Well, that took a long, long time. Quite a thick seatpost. Half a tub of caustic soda and 3 weeks later... :)

This SR Laprade seatpost was stuck in my Major Nichols frame. The previous owner had put the seatpost in too far with the bottom of the flutes below the top of the seat tube and the weather had got in and seized it in good. It's taken over 2 weeks of the caustic soda treatment to get it out.

blimey, i am sizzling mine as we speak, hope it don't take that bloody long.
will let you know

I had a seized seat post not long ago; I didn't dare do the caustic soda option but I can tell you that sawing down the post (or using a file) and then using a pair of mole grips does work. When you're using the moles grips wrap the post in sandpaper for extra grip.

blimey, i am sizzling mine as we speak, hope it don't take that bloody long.
will let you know

Good luck mate, I really hope you don't have to wait as long as I did. Really glad I waited tho and didn't start chopping it up. The seatpost may look a right state but the frame is completely undamaged.

it is starting to work,
serious fizzing going on.
and it has not marked the powder coat.

Yeah, after about two days the fizzing will start to get less and less and when you pour it out it will be all murkey with aluminium oxide. Then in with a fresh batch and it'll start fizzing away like mad again.

Had a vice clamped on mine wich I beat the hell out of with a hammer every time I changed it and nothing untill the day it started leaking through between the seat post and tube and then all it took was a gentle tap on top with a hammer and then twisted right out.

The paint on mine is the original from 1969 and the caustic soda didn't do it any damage. Only problem I had was I spilled some on one of the decals and it did do some damage there.

a word of warning

don't do this wearing berkenstocks, unless you want craters in your feet!!! stings like fnck :)

seems to be working ok.

yipeeeee!!
all done, 26hrs total, filled tube with mixture, emptied then re-filled 3 times. roughly 8hrs apart
flushed out after with loads of water
then squirted in loads of WD40
left for 15mins, emptied upsidedown for 15mins, repeated.
lightly filed the inside of tube.
re-greased and fitted, no probs.

1 Attachment

I have a massive long peice of angled steel, which convieniently has holes the same point as the bolts for the clamp on my post. So I thought I would give the leverage idea a go, It seemed the most scientific option to me. a shit load of pressure applied to the end of a long bar had to be more than enough to break the seal of a but of corrotion, instead the corrosion didn't budge but the weld of the clamp to the seat post gave way and now not only is my post stuck but the seat wobbles all over the place when I ride.

So looks like I am gonna have to try and cut it out but I am shitting myself, when you eventually get through the post is it obvious? how will i know I aren't also cutting my frame in half? Its 531c so the tubing is gonna have thin walls. also how many cuts do you need? will the sections just peel off the sides once I cut through?

Currently playing this game too. When I clamped the seat post into the vice and turned the frame, the whole seatpost twisted and buckled. Now it's cut off at about 1cm above the frame (which is a pain because it's tough to plug) with the second dose of caustic swilling away inside.

Tried sterident on stuck quill stem as I wanted to see if I could save the stem. Left it or a week and then occassionlly changed the water when I remembered a, it fizzed gently and now it came out.

May work or may not but it worked well in this case a I didn't want to try too force the stem too hard in case I damaged the forks.

Have another stuck quill stem and its been soaked on caustic soda but now no longer fizzes but still doesn't want to come out.

What to do next?

So looks like I am gonna have to try and cut it out but I am shitting myself, when you eventually get through the post is it obvious? how will i know I aren't also cutting my frame in half? Its 531c so the tubing is gonna have thin walls. also how many cuts do you need? will the sections just peel off the sides once I cut through?

don't bother wasting your time trying to cut it out.
just cut in fairly near the top of the seat-tube, and fill with a mix of caustic soda and water, right up to the top.
change it every day until it has burnt it all away.

oops, is it a lugged frame?
if so you'll have to remove the b/b and plug it.