Siezed seatpost - drastic(ish) method

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Siezed seatpost - drastic(ish) method

19 posts & 17 voices | Started 2 years ago by Twirlip of the Mists | Latest reply from racemonkey

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Twirlip of the Mists - Member

My seat post is stuck in my frame. It's been there for a while. Thus far it's endured treatment with amonia, boiling water and shouting and swearing without budging.
People have suggested drilling a hole in the seat post, putting a rod through the hole and twisting but I'm worried that I'll just end up bending or snapping the post and the bottom half will be stuck in the frame forever.
I do have an idea though. I've got one of those blow torches for making creme brulee. Would applying that to the seat tube and an ice pack to the seat post:

a) maybe, free the seatpost?
b) melt something?
c) make something nasty happen?

All advice, experience and anecdotes gratefully received.

--Matt

Posted 2 years ago #
momentum - Member

It will obviously fubar the paint, but apart from that it's worth a try. Final option is to dissolve it from the inside with caustic soda. I posted about that a little while ago.

Posted 2 years ago #
CaptainMainwaring - Member

Borrow or buy a reamer and very carefully ream out the seatpost until its so thin you can bend it in on itself. Mate of mine had to resort to that recently. Alternatively take it to a good bike shop who will do it for you

Posted 2 years ago #
bent_udder - Member

Aluminium or steel frame? Have you tried Plusgas, Coke or similar? How much seatpost is left - have you chopped it off, or is it intact?

Posted 2 years ago #
swamp_boy - Member

I shifted one that had been in for about quite few years by standing astride the bike facing backwards to stop it moving then twisting the post with a big pipe wrench [24" Stillsons]. If you just have the stripped frame putting it in something like a workmate might help but you'll need to stop that moving. Once it starts to twist you can work it upwards. Mine took some heaving and grunting but it went in the end and the Stillsons didn't crush it, which had been a worry

If you can get some fine penetrating oil down between the post and the frame tube it will help.

Posted 2 years ago #
ajantom - Member

Rather than using a blow torch, use one of those hot air guns designed for taking off paint, etc. It builds up the heat more gradually, and because it's an element heating the air, rather than a naked flame, it won't muck up the paint job. I used one recently to help shift an old steel BB that had welded itself in an aluminium flame and it worked a treat.

Posted 2 years ago #
coffeeking - Member

My experience with such a stuck post almost bent my frame, heat buggered the paint and I stopped with the heat/force method there. I chopped the top off the post, leaving an inch or two showing, then cut down its length axially, as far as I could, without hitting the alu frame. This took HOURS and careful observation. When I'd done what I could, I grabbed one side of the cut and twisted the post in on itself. This cracked the post in half length ways but freed the bond and I was able to tap the rest out. I was fortunate in that it was a pierced seattube frame though, so I coudl get at it from both ends.

Posted 2 years ago #
smartay - Member

A conbination of the above seems to do the trick, frame in vice and heat the outer and stillies on the seat tube.Local garage etc for oxy acetelene/propane.
Paint may not look its best afterwards.
I take it the frame is steel.

Iknow this doesnt help at this stage but why do people leave their seat tubes in, quick release!!

Posted 2 years ago #
nostoc - Member

I don't see how applying creme brulee to the seatpost could possibly work

Posted 2 years ago #
tonyplym - Member

Had success in the past using a small pneumatic chisel applied upwards to the underside of a gash saddle fitted atop the seatpost - the high frequency jolts gradually worked the post loose (took a couple of minutes, but left little or no damage); combine this with a good soaking in Plusgas or similar, and some gentle heat (try wrapping an old towel tightly around the frame tube and then soak it with a kettle of boiling water). If you haven't got an air chisel try using a hammer drill (put an old bolt in the drill chuck; bring to bear upwards against a block of wood under the gash saddle).

Posted 2 years ago #
Kinavit - Member

My lbs once suggested getting some vinigar from the chippy before they water it down, as this will apparently desolve the corrosion and free the post. Not tried it so can't comment, just passing on what I was told.

Posted 2 years ago #
Drac - Moderator

Clamp the seatpost in a vice and turn the frame.

Posted 2 years ago #
slowrider - Member

are you ok with wrecking the seatpost? if so, there is a way that doesnt risk damaging your frame half as much as some of the above methods:

saw through the seatpost roughly an inch above the seatclamp.
remove the seatclamp.
file down the rough edge of the seatpost if you can be bothered, it saves your hands a bit.
saw a vertical line down the seatpost, going in to the split where your seatclamp was (the bit that your seatclamp pinches together).
once you have gone right down to the bottom of this split, stick the saw blade down in to the frame and continue cutting the seatpost, following the guide you have made with your vertical cut. do this 2 or 3 strokes at a time so you dont cut your frame. the seatpost will come out easy once you have cut through it.
check the insude of the post for scratches and give it a fine sand or whatever it needs.

hope this helps!

Posted 2 years ago #
andywarner - Member

i gave mine to a mechanic mate to do who said it would take him a couple of minutes. when he brought it back he told me it had taken 2 of them 3 hours to get it out. i felt a bit guilty to be honest...

Posted 2 years ago #
bent_udder - Member

Coffeeking and Slowrider have the best recommendations so far - I've used this method on a friend's aluminium frame in the past after another friend suggested a 27.4 seatpost would fit a 27.2 frame. It took us a long time to gradually saw through the post from inside, but it did come out in the end. We put the frame on a workbench so the seattube was horizontal, and gradually cut in with a hacksaw blade.

Posted 2 years ago #
Twirlip of the Mists - Member

It's an 7005 aluminium frame and an aluminium post too. Quite a thin walled race face post so sawing should be easy. It's stuck at almost the right height but I don't like it there and, since I broke a similar post in my other bike, I don't think much of the post design either.
It's an '03 Kikapu so there's no paint to spoil on that bit of the frame.
Thanks for the suggestions. I'll work my way down the list from least to most drastic and let you know.
Cheers.
--Matt

Posted 2 years ago #
avdave2 - Member

I've cut one out before and it was so bad it took several vertical cuts before it would come out. If your careful a reciprocating saw can save a lot of time and blistered hands. If your going to try the heat method then try using pipe freezer first. I've freed a seized tap using that followed a couple of minutes later with boiling water. It gives a much bigger temperature change in a very short time.

Posted 2 years ago #
rich-6 - Member

Hammer it in a bit if you dont mind damaging the post, It'l free it allowing you to pull it out

Posted 2 years ago #
racemonkey - Member

Second what Drac said.
Put the post in a decent vise and crush it and use the leverage of the frame to release it.

Done this twice to free alloy posts that had 'grown' into steel frames (and have the pics to prove it).

Posted 2 years ago #

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