Stuck Seatpost

[adamhell]

Hello.

I got this trek 950 f/f/hs for $100. The seatpost is stuck. I brought it to boxdog bikes here in SF and they tried penetrating lube, puttin it in the vice and trying to rotate the seatpost off, which didn't work. they then used ammonia in place of penetrating lube following the same thing in the vice, and still no dice. the seatpost is cracked vertically, which makes me think somebody tried to get it out before me.


people are telling me the last options are A) drill it out, or B) heat the seattube around the post (which is almost fully sunken into the seattube) which will somehow release it. There is a third option, (C) put the frame in the trash and absorb the $100 hit, followed by the need for another cheap steel 90's mtb frameset.

I prefer (A) because it wouldn't ruin the paint, but think it would take a while.

What do YOU recommend / advise?

[Dead Man]

Is it just an optical illusion or is that a shaped post?

if it's normal round, you could try drilling a hole through the pin and running a bolt through it, chuck the bolt up in a bench vise, light the seat tube and twist... it'll come out if you use enough manliness.

I had a carbon pin that was absolutely fused to an aluminum insert in a titanium bike - I think previous owner said bike shop couldn't even get it out... I didn't need to drill, because it wasn't all deformed like that one is (I just thinking clamping that thing in the vise is likely to make it HARDER to get out).. knew the pin was almost surely ruined anyway... stuck it in the vise, hit the seat tube with my MAPP torch and heated it up just enough to expand the metal some, but not ruin the temper... then I grabbed the head tube with one hand and the chain stay with the other and gave that sucker a massive twist.... CCCCCCCCRRUUNNNNCCCCHHHHHHH.... slid out.

Just make sure you don't heat it up so hot you hurt the paint. You're just trying to get the metal tubing to expand some, not melt the thing. If it wasn't so big, you could throw the whole thing in the freezer first and then chuck it up and throw some heat on, that'd work even better... but I'm betting you don't happen to have an empty deep freeze that'll take a friggen bike frame.

[p nut]

I've never had any success with any of the methods you outlined. The last bike with a stuck post, I just ended up giving it away. Now, I have HEARD that better, but more time consuming method is to:

a) cut the seat post just above the seat tube.

b) use a hacksaw to carefully cut away vertically at the seat post from the inside, making sure not to cut the seat tube itself.

c) cut it into 4 to 8 pieces and peel it away from the seat tube.

Never tried it, but sounds like it would work. Just need lots of patience.

[Big Dan]

Put the seatpost on the vice (fixed to a workbench) and rotate frame.

[ColonelJLloyd]

Have you tried Freeze Off? This is what I used to remove the most stubborn seatpost I've dealt with. It's available from any auto parts store.

[fishbolish]

i removed a thompson seatpost that had been cut flush on a steel 616 fab fatbike, ifound on youtube the removal using lye( potassium hydroxide)

sealed the bottom bracket with a wedge and a wood half moon plug (used an old piece of inner tube inner tube as the seal) , used allens to plug water bottle holes.. i made a periscope off the top of the seatcollar out of rubber plumbing fixtures & pvc

its a MESSY,NASTY job ....a paint respirator is needed as the caustic fumes can be dangerous ......goggles and rubber gloves are needed as well

took a long morning of applications..but it worked( rise tubes well with water
when done)


the question is,is the frame worth all this ?

[adamhell]

Originally Posted by Big Dan

Put the seatpost on the vice (fixed to a workbench) and rotate frame.

this has been done after penetrating lube and ammonia. still no dice.

[adamhell]

Originally Posted by fishbolish

the question is,is the frame worth all this ?

no not really.

[adamhell]

it's not a shaped post, it has just been clamped and twisted already so it's no longer round. i'm probably just going to trash this frame.

[David Kirk]

Can you stick something down into the post from the top so that you can get a rough idea of how far the post is in the frame?

dave

[OtayBW]

Originally Posted by ColonelJLloyd

Have you tried Freeze Off? This is what I used to remove the most stubborn seatpost I've dealt with. It's available from any auto parts store.

Or LN2.

[adamhell]

Originally Posted by David Kirk

Can you stick something down into the post from the top so that you can get a rough idea of how far the post is in the frame?

dave

yes i will try this later. i have a feeling it's about 250mm down there due to how low it is in the frame.

[YoKev]

Vertical slits with a hacksaw blade. It may take some time but it'll be worth it IMHO. That's a nice frame! I have surgically removed three posts and a quill stem with this method.

[adamhell]

Originally Posted by YoKev

Vertical slits with a hacksaw blade. It may take some time but it'll be worth it IMHO. That's a nice frame! I have surgically removed three posts and a quill stem with this method.

so let me get this straight - i have to remove the hacksaw blade and dip it down into the seat tube and start sawing away? how do i get leverage on the bottom end? this seems like it would never work. maybe i am misunderstanding something????

i'll try it later tonight

[Gsinill]

If the part that is sticking out is useless (which it seems it is since the vise method didn't work), did you try to use a mallet to drive it in further?
I am sure if you get it to move just a little, it would free it enough to then twist it out in the vise.

Man, and I thought my seized BB is trouble!

God Luck!