Seat post fused with frame - suggestions?

onimpulse

Hi Folks,

Just wondering if anyone has a solution or suggestions - The seat post has fused with the frame of my bike - a carbon frame. I need to raise the saddle slightly, however it's totally stuck.

I've tried Pulling, pushing, hitting - I even put the handle of a brush into the piece that holds the saddle & tried to use that as a lever but no joy.

I know it's not the first bike this happened to but I've yet to hear of anyone who solved the problem. Hopefully someone here can help?!

Thanks!

furiousox

Isn't there some theory about pouring coca-cola down the seat tube and leaving it overnight?
You'll need to google it for the exact method.

Dizraeligears

I had this problem a few years ago...carbon post stuck in carbon frame.
Coca cola did it for me.Wrapped a cloth around the frame just below the seatpost collar so it didnt go allover the place,then poured it slowly around the seatpost/frame join.Be patient!

arodabomb

As a general rule I refer to this diagram in all walks of life.

oflahero

arodabomb wrote: »

As a general rule I refer to this diagram in all walks of life.

Slight point of order but please see no. 47 with regard to that pic.

Diarmuid

I recently had an alloy seat post stuck in a carbon frame. Took it to the shop, it was too messy a job for me. You need to cut the post then use a long sharp screw driver and work on the inside of the seat post for a while until you weaken the post and then squeeze it with a pliers and it should come loose. Very messy and labour intensive. Take it to someone who has done it before.

I took it to Joe Dalys

el tel

Would Pepsi work instead of Coke?

RidleyRider

el tel wrote: »

Would Pepsi work instead of Coke?

Would diesel work in a petrol car?

doozerie

Suggestion 13 of this list is interesting. It suggests that pulling a seatpost out of a carbon seat tube is made difficult by the seat tube stretching and essentially "shrinking" around the seat post. The solution is simple enough. In that particular case though, twisting the seat tube was not an option due to its shape - the fact that you can't rotate your seat tube may suggest that your situation is more serious/difficult though so the same solution might not be relevant for you. One/some of the other suggestions might be useful though even if that one isn't.

Al Wright

It is very difficult to pull a seat post out of a carbon frame, due to the tendency of the frame to contract and hence grip the post.
The best method is to make a collar to fit over the seatpost at the frame end and to push off the frame as illustrated in sketch. Possibly your local bike shop may have the specific tool available

cython

When stretching and contraction is mentioned, it brings to mind another suggestion I have heard of for breaking the carbon/alloy bond as described, and this is to pour moderately hot water (not boiling mind) on the interface, and the relative differences in the rates of expansion and contraction of the two materials may force apart the bonded parts relatively gently, and slow you to remove it.

Brian?

Stupid question: Have you loosened the clamping bolt all the way off? I realise the the answer is probably yes, but these things need to be asked.

If yes:

1. Spray WD40 around where the post meets the frame. Let it sit for a while, WD40 is a degreaser and a mild solvent so it will need time to work.

2. Can you get your hands on Isopropyl alcohol or similar? If you can use that.

I'll qualify that with a disclaimer that I fix things(rather high precision manufacturing equipment) for a living, not bikes.

Edit: Is it cyclindrical seat post?

leeomurchu

Spray on WD40 leave it soak in for a while maybe over night and then if you can twist the saddle from side to side to get the wd40 in around after that twist and pull

If all else fails break out the persuader and try to avoid splinters

doozerie

cython wrote: »

When stretching and contraction is mentioned, it brings to mind another suggestion I have heard of for breaking the carbon/alloy bond as described, and this is to pour moderately hot water (not boiling mind) on the interface, and the relative differences in the rates of expansion and contraction of the two materials may force apart the bonded parts relatively gently, and slow you to remove it.

You need to be careful with heating, or cooling, two different materials - if the seatpost expands faster than the seat tube, or the seat tube contracts faster than the seatpost, then there is a risk that you could crack the seat tube. It'll obviously depend on the materials so check their properties first.

In step 13 of that post that I linked to above though, it is stated that carbon is extremely (thermally) stable - if that is correct, then you are likely on a hiding to nothing if you try heating or cooling options.

tdo

cython wrote: »

When stretching and contraction is mentioned, it brings to mind another suggestion I have heard of for breaking the carbon/alloy bond as described, and this is to pour moderately hot water (not boiling mind) on the interface, and the relative differences in the rates of expansion and contraction of the two materials may force apart the bonded parts relatively gently, and slow you to remove it.

This definitely worked for me some months back on a carbon seat post stuck in an aluminium frame for some years. Several kettles of boiling water on the down tube and a lot of brute force from my brother and I and we managed to get it out. Don't know what neighbours thought of all the grunting and roaring

Not sure if would work on carbon on carbon, and certainly wouldn't recommend boiling water.

Lesson learnt, now check the seat posts on both my bikes every few months.

tawfeeredux

tdo wrote: »

This definitely worked for me some months back on a carbon seat post stuck in an aluminium frame for some years. Several kettles of boiling water on the down tube and a lot of brute force from my brother and I and we managed to get it out.

I need to do the same with a carbon seatpost stuck in a steel frame. Is there any danger of the hot water damaging the paint work on the frame?

cython

tawfeeredux wrote: »

tdo wrote: »

This definitely worked for me some months back on a carbon seat post stuck in an aluminium frame for some years. Several kettles of boiling water on the down tube and a lot of brute force from my brother and I and we managed to get it out.

I need to do the same with a carbon seatpost stuck in a steel frame. Is there any danger of the hot water damaging the paint work on the frame?

Any of these thing probably carry some risk but if you're really wary start at relatively low temperature and work up to the coldest possible that does the job if you can hit it before you get really worried about the temp

Mugser

Bit of a resurrection here but I'm currently working on a bit of a fixer-upper, a Giant Sierra MTB from the late 80's early 90's. Problem is the Aluminium seat post is seized solid into the steel frame. Some goooooooogling has suggested removing the bottom bracket, turning the bike upside down, pouring some ammonia into the seat tube and leaving it for 48hrs. Is ammonia even available off the shelves here? Or better still, any other suggestions?

Craig06

Global cycling network did a video on YouTube how to remove a stuck seat post recently.

07Lapierre

Mugser wrote: »

Bit of a resurrection here but I'm currently working on a bit of a fixer-upper, a Giant Sierra MTB from the late 80's early 90's. Problem is the Aluminium seat post is seized solid into the steel frame. Some goooooooogling has suggested removing the bottom bracket, turning the bike upside down, pouring some ammonia into the seat tube and leaving it for 48hrs. Is ammonia even available off the shelves here? Or better still, any other suggestions?

Are you looking to remove the seatpost with out damaging it? I'd sacrifice the seatpost by clamping it in a vice and use the frame as a lever and twist the frame off the Seatpost.

If that doesn't work....nothing will.

Mugser

07Lapierre wrote: »

Are you looking to remove the seatpost with out damaging it? I'd sacrifice the seatpost by clamping it in a vice and use the frame as a lever and twist the frame off the Seatpost.

If that doesn't work....nothing will.

Bit of brute force will be key so:) Sound like best course of action.

Hunterbiker

Don't you have to be careful with WD40 on carbon components? Im sure I read that somewhere

el tel

Hunterbiker wrote: »

Don't you have to be careful with WD40 on carbon components? Im sure I read that somewhere

You certainly didn't read it here www.wd40bike.com/products

Kav0777

I can't believe no one on this forum has suggested a new bike, it's the most flimsy perfect excuse ...


What has happened to this forum, you've all changed, you should be ashamed of yourselves....

Cee-Jay-Cee

I think the best all round option would be to buy a new bike.


On a side note, would it be preferential to remove carbon seat posts from carbon frames every so often and to reapply grip paste to ensure it doesn't become stuck?

DKO

I got an aluminium seatpost stuck in a carbon bike a few years back. Over the course of many hours working with a few files varying from coarse to fine I managed to file it out. I still have the remnants somewhere as a warning :-)

I had tried coca cola into the seat tube left for ages amongst other approaches, cooling it and heating it rapidly, a bit of brute force and not a budge. I even tried with another lad to twist and force it out deciding that if the frame broke screw it, the post didnt shift and we could'nt break the carbon frame! But patience and those files got it in the end :-)

There was only very slight damage to the very top of the carbon in the tub, just aound the bit where the seat post clamp goes and the bke performed fine again once it was sorted.

whacker00

Craig06 wrote: »

Global cycling network did a video on YouTube how to remove a stuck seat post recently.

http://www.youtube.com/watch?v=54WhdrLKKvY

TiBoy

Try packing the area around the seat post and seat tube with crushed ice and repeat a few times when ice melts.

This is a little known trick to separate stuck sections of carbon fishing rods.

Essentially the same problem, carbon stuck in carbon, so might work on the seat post....