Stuck alu seatpost in carbon frame

penetrating oil, plus gas is a goody, or wickes do their own brand of it.

remove as much crap as you can before spraying it on and leave overnight.

works for me.

wd-40 is not penetrating oil.

Tap the top of the post with a hammer, the shoch should break the bond between the post and the frame.

Tap the top of the post with a hammer, the shoch should break the bond between the post and the frame.

+1

Also recommended when stuff won't budge. Hammer it gently downwards to break the chemical weld.

After freezing it.

I removed the seatpost. At the outset, I should say it was impossible to remove it through other means given the risk of cracking the carbon frame. However, the method I eventually used to remove the tube was destructive. I will get the frame thoroughly checked before I even consider riding it.

*Method: how I did it

• 
  Here's the tools I used.
  
  

Hammer, narrow short & long screwdriver, metal hacksaw bit & plastic handle and torch.

• I began by cutting off the seatpost one inch above the seat tube. With the torch, I tried to guage how long the postwas stuck in the tube. I made a mark on the blade at the same length as the seatpost so I wouldn't over-cut into the frame accidentally. I then slowly started cutting the first slit through the tube. It took a while to get going, the difficult part is to keep pressure evenly all along the post, top and bottom. It took ages, but after 40 minutes, I had a nice groove going. I would keep checking the depth of the slits with a torch to ensure I didn't start cutting the tube.
  
• I kept going until I thought I was micrometres from cutting through the tube. I then made about four more grooves every 5mm making four strips. The theory was to nearly cut through the tube making it possible to lever them out with a wedge.
  
• After making 5 grooves, I started carefully wedging a narrow, short screwdriver between the seatpost and the seat tube; I gradually hammered the screwdriver into the tube. The first strip broke off and fell into the tube.
  
• I repeated this as the opposite side and the same thing happened.
  
• By that stage, removing the rest of the post was a matter of grabbing it with a pliers and pulling it out with a little force.
  
• On inspection of the remaining seatpost, I could see that the post had completely glued to the tube. Unfortunately there was some damage to the bike, so now I'll have it fully inspected to see if the frame is now usable.
  
  
  
  

Photos of the job are below

Outside seatpost covered in rusty, sticky, mouldy goo.

Left shard was the first removed, the rest followed. Only one half of the tube was cut.

*The needle and the damage done: some striations and very shallow chips on the
seatpost housing and the beginning of lots of rust and goo in the seat tube.

*QUESTION: What's the best way to clean out the gunk from the seat tube?

Well done ! I too have an old Look frame with an alu seatpost. So when I first read this thread I checked it as I've not touched the seatpost in about 4 years, so undid it and yes it's stuck !

Luckily it's stuck at the right height.

Nice one!

Well done ! I too have an old Look frame with an alu seatpost. So when I first read this thread I checked it as I've not touched the seatpost in about 4 years, so undid it and yes it's stuck !

Luckily it's stuck at the right height.

Tell me, the screw-in yoke in the top of the seat tube you use to tighten the seatpost - it's missing in mine.

What replacement do I need? Where could I get one?

Not 100% but this may do the job.

http://www.allterraincycles.co.uk/product/105619.html

Well done ! I too have an old Look frame with an alu seatpost. So when I first read this thread I checked it as I've not touched the seatpost in about 4 years, so undid it and yes it's stuck !

Luckily it's stuck at the right height.

I think I read somewhere that if you get your seat post anodised, it prevents corrosion in the carbon frame. Whatever anodising is.

fair play! well done on getting it out. Now u have a pukka frame !

u can see the galvanic erosion on said seat tube...

see if u can get a small wire brush that'll fit in the seat tube. that should do the trick as far as cleaning it goes.

and when u come to using another seatpost, use carbon assembly paste.
that'll prevent future problems with stuck seat posts.

I think I read somewhere that if you get your seat post anodised, it prevents corrosion in the carbon frame. Whatever anodising is.

not entierly true. anodised post endure *slowe*r galvanic erosion, but it still erodes.

not entierly true. anodised post endure *slowe*r galvanic erosion, but it still erodes.

Righto. So, basically, lube it up with graphite and keep checking the tube fairly regularly. Sound oush.

from what i've read, yes, that about it.
avoid grease, apparently, like the plague.

Not 100% but this may do the job.

http://www.allterraincycles.co.uk/product/105619.html

All Terrain Cycles say this'll work. Thanks.

I stick copperslip on the seatpost... no chance of it getting stuck then. Copper Slip is specifically anti-seize.

from what i've read, yes, that about it.
avoid grease, apparently, like the plague.

Yup, will render carbon parts ultimately useless, forever (or so I'm told)

Yup, will render carbon parts ultimately useless, forever (or so I'm told)

Yeah, I'll get this frame checked by someone to ensure it can be used.

Any ideas about how to thoroughly clean out this manky seat tube? It'll need to be de-gunkified, but not sure what I should use that won't damage it.