"Fused" seatposts.....

[HomerSimpson]

We have probably all come across the phenomenon of seatposts apparently immovably fused to frames....

 

I know why this happens, and I also know what should be done to prevent this from happening.....

 

What I want to know is:  what can be done to get thing loose again?  Other than having the post drilled out?

 

 

[Guest Big H]

For aluminium seatposts you coat the post verrrry thinly with a grease like the Park bicycle grease. You do this often as part of your regular maintenance. carbon Fibre use other methods..... DO NOT USE GREASE.

 

To get them loose again use a penetration oil like WSD 40 or Q10 and use lots of it, try to get oil in from the bottom as well. Remove the BB if neccesary. Leave it overnight and try to remove. I do not think drilling out is really an option as damage to the frame will be irrepairable.

 

Many frames have been junked due to not enough maintenance.

 

Added later...........

 

Oops!!!!!!! ............ ek sien op Widget se anner post oor die boot enjin dat Jan Boreman alreeds daar weer se ekke praat strint!!!!!! Die aksie is wel dalk nie galvanies nie maar kan elektrolities wees. Jannie is gewoonlik reg en nie heeltemal mens nie want mense maak ook foutjies!!!!!!!

 

Probeer maar die Q10 WSD40 dit is dun olie en dit werk dalk.

Big H2008-03-12 01:18:19

[lowracer]

this might be of use specifically to seatposts and bicycles

http://www.sheldonbrown.com/stuck_seatposts.html

[Johan Bornman]

With modern thin-walled frames Sheldon's method of using the frame as a lever, you are in danger of bending the frame. I've seen a seat tube twisted like a licorice, with the seat stays following suit. Not very aerodynamic.

 

If it is an alu frame or alu seatpost, you WONT get it out again without destroying the post. Come to terms with it.  If it doesn't move at all when you twist the saddle, it is there for keeps.

 

Drilling also doesn't work, nobody can dril that accurately if they don't have the object fixed to an accurately aligned jig.

 

The correct removal method is to saw off the post about 5mm above the seat collar. Then, with one of those hacksaw blades with a handle (or a blade with a rag), you carefully saw through the post down the entire length of the post.  Easier said than done. Be patient. If you become in the least impatient, go rest and drink a beer. Windhoek works best.

 

Once you've sawn through the entire post, you roll the seat post up by gripping one of the ends near the new slit with a pliers and with a rolling motion, roll it up into itself. You'll notice that the oxide that expands wildly doesn't make a good glue. The two surfaces separate quite easily but won't slide over each other at all.

 

Pray that the aluminium post doesn't break off on the pliers. Although you can then try from the other side, you only have two lips to grip and once both are broken off you're in dynamite territory.

 

Don't waste your time on penetrating preparations.

Johan Bornman2008-03-12 03:30:12

[Spinnekop]

Simple rule which my educated colleagues above won't approve off.....

 

The bigger the "fuse"......the bigger the hammer!! 

 

[GoLefty!!]

I find Whiskey to be more effective than Windhoek.

 

The same method works for Carbon posts in AL frames and vice versa.

 

Good post Johan

 

Another method is to take advantage of different expansion rates of the material so either cooling one more than the other or heating it up.

 

Always use CopaSlip when assembling parts of different materials especially if you're sweating all over it.

[HomerSimpson]

Tnx guys.  Was pretty much committed to the sawing off and out method.  Old cro-moly frame and Alu seatpost.  Might give cooling the seatpost with CO2 a bash before I launch the saw effort.  JB, will Windhoek Draught be OK, or is Lager better?  I refuse to drink Windhoek Light. 

[tubed]

Clarification:

 

use the alcahol of your choice, but do not pour into frame and wait for 'loosening effect' - it will have no effect on the frame and be wasted

 

pour alcahol carefully, but directly into operator, when 'loosening effect' achieved - go back to step with saw 

[bob_the_builder]

Windhoek works best.

 

 

A whole new respect JB