Seized Seatpost. Plan of attack.

[smithchild]

On my Marin Palisades 91, stuck fast

My initial idea would be to;

turn bike upside down.
spray plus gas into the seat tube through the bottle cage holes.
leave over night.

then..

drill a hole through the post.
stick some sort of lever through said hole.
lever.

but, i have never had success in the past so any experienced ideas gratefully received. what's the generally held consensus as to what order to resort to different techniques?

 

[Ihatemud]

and warm it up too!

do what you suggest but dont do the hole thing - if its a alloy seat post it will just snap off

I would put the seat back on and use that to gentle wiggle it

before you start wiggling warm the seat post up with a blow torch ( map gas is hotter than propane) and squirt more plus gas down from the top (not aerosol) and

XXXXXXXXXXXXXXXXXXXXXXX
dont ignite the plus gas! especially if you have got it on your hands and clothes!
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[perry]

i would hire a stil saw and cut the seat tube out while manically waving said saw above your head cackling with insane laughter , take an old broom and wrap tape around it so the sticky side is out , inset in new seattubeless frame , wrap tape round it again but the correct side down this time , remove broom and hand back to mrs . carefully fit seatpost and clamp in now seizeless tube ( careful not to dent the new "tube" )

or use the search feature , not like someone gets a seized post every fortnight

 

[smithchild]

soz, did try the search but it didn't seem very user-friendly
(couldn't work out how to just search thread titles - someone will point it out in all its glaring glory now)

i'm going to put off heating till a last ditch attempt because the paint is the zoncalon stuff and I want to keep it original if poss.

 

[hamster]

It's a week's project.

Dismantle the bike and clamp it upside down in a vice. Accept that the seatpost is a goner. Take the BB out so you can pour lube down the inside of the seat tube.

Pickle it in Plusgas and giving it a wiggle every morning and evening for a week often loosens it. One you can get the post to turn you WILL be able to get it out.

After plusgas try pickling with Pepsi.

After pepsi it's down to sawing out the post from the inside. Take your time.

There are plenty of threads on this one.

 

[OldFatTi]

Heating the seat tube around the post area with a heat gun will help too as the steel will expand slightly.

Should be pretty easy with time and constant lubing/heating/twisting. If still no joy, there's always caustic soda....

 

[hamster]

Heating the seat tube around the post area with a heat gun will help too as the steel will expand slightly.

You have to be quick with this one as Alu expands more. A rag soaked in very hot water works well.

But applying heat to get it all to move a little is a very good start. Similarly shocking it with plumbers' freezer spray can help....or even better pop the frame into a chest freezer overnight, then do the hot rag trick.

 

[Splatter Paint]

OK, first of all have a browse at Sheldon Brown's stuck seatpost page, that really helped me a lot. I have cut posts out in the past, but any marks made in the frame show up on the new seat post

I did the last one by turning the frame over, plying loads of pentrating oil through the water bottle bolt holes and leaving for 24 hours. Then I wrapped a towel around the frame and poured loads and loads of hot water on the towel so the frame stayed hot. It was freed using a twising motion by a very large adjustable spanner on the seat post and using a slide hammer teathered through the hole at the top of the post where the clamp goes on the saddle rails.

My seapost only had 1" plus the clamp showing from the frame and was out, without damaging the frame within 20 minutes. Keep the bike as complete as possible, it'll give you more purchase to lever on.

If all else fails it is out with the hacksaw blade I'm afraid. Good luck, it isn't a nice job.

 

[Pip]

Not really a viable option for a lot of people but I have had posts machined out before (assuming ally post in steel frame here). Otherwise its a hacksaw and a lot of patience!

Pip

 

[drystonepaul]

I got a siezed alloy post out of a cro-mo frame yesterday. Removed the saddle and clamped the post into a big old bench vice with some nice soft shaped blocks of wood. I then poured lots of penetrating oil down the seat tube.
Left it for a bit and then got bored and so I ended up removing the wood to give added vice like grip and twisting the post out using the frame for leverage.
I did originally want to save the seatpost by using a bit more finesse and patience, but as I say; I got bored with the waiting.
So the post is a goner but the frame will live to fight another day. The seatpost wasn't really period correct anyway...