Corroded seat post

[magas]

great pictures magas!! they should be put in a sticky post for other people

thanks !

agree, that a photo documentation of the procedure of removing a stuck seatpost from the frame, also what tools should be used, would help a lot of people and would also reduce the no. of threads in the future.

 

[Pip]

Most has been covered above, but in extreme cases you can machine out the old post, but it is a b*stard (engineering term) to do. Caustic soda works very nicely on steel frames with a alu post, though prepare to sacrifice your paint job a little, but as mentioned for the love of god dont put it in a alu frame!

Word of warning with the heating the frame/cooling the post/twisting thing. It is quite possible that the bond between the post and tube is strong enough so you could fold/deform the frame tubes by twisting it, BE CAREFUL! I have seen it happen! Also im not sure the heating/cooling thing would have much effect. It works on alu/steel bonds as they expand/contract at different rates. So as you are trying to break a bond between alu and alu I would not expect to gain much advantage off it.

If its the right height there is a lot to be said for leaving it!

Pip

 

[ashridge]

Thanks for all the advice.

Of all nights to work late this wasn't a good one because I had visions of a molten amorphous blob sitting on the floor of my shed.

As it is there is not a scratch on it - phew!

I have emptied half a tin of GT85 into the bottle cage hole and will let nature take its course. I know my friend tried WD40, but he tried it right way up rather than inverted.

I thought about warming the frame but had rejected it on the basis that the seat is alloy too. Maybe the different grades and thicknesses of Al may make a difference...

Why I am spending so much time is twofold: firstly the seat is about 2-3" too high for either of us and secondly I would actually like to buy the bike from him as a second project frame.

 

[sam264]

in a book i have on mountain bike maintenance it says to get a bench vice screwed into the bench (has to be sturdy), clamp the seatpost in the vice and twist the frame which will give you a LOT of leverage. I haven't tried it, but i see no reason why it can't work.

 

[stew-b]

why use gt85? its a lubricant not a penetrating fluid,you should have used plus gas :roll:

 

[Splatter Paint]

Alloy on alloy is a pain, is there a mild acid that would do the job? I've heard rumours of Coke being used but what about vinegar etc? Personally I'd only ever had stuck posts in steel frames which were removed using the hot water or in extreme cases hot air gun and the twist / pull method.

Why don't people grease seatposts or for that matter bottom brackets? :roll: