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  1. #1
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    Salty Frozen Seat Post

    Well my seat post was absolutly frozen into the seat tube...from last winter...I guess I need to wash and rinse a bit more and maybe move things a little bit...

    Anyway I noticed this last week....generally I will raise the seat a little for road rides and commutes and drop it for mountain rides...and maybe a bit more for downhills...point is I move the seat up and down on a seekly basis over the summer.

    So if the post is frozen the frame is going the way of the dodo bird..

    So I got out a kettle and steamed the seat post.......then with a big hammer whacked the nose of the saddle and bingo it moved just enough to till it was crooked...

    Anyway CLR, carb cleaner and lube were added....but basically steam and a hammer was the only thing that worked...

    Took me about 2.5 hours, and a really good core work out to get the thing out...

    A quick wipe with 120 grit and steel wool some grease and it is working fine again.

    What happens is the aluminum corrosion product has a larger volume than the aluminum metal so when a pit forms they really lock togeather tightly.

    The saddle nose leather was a bit separated so I srapped it with electrical tape...if that doesn't work I will get a new saddle.

  2. #2
    I Ride for Donuts
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    Are the frame and post both aluminum? I've heard that's a real nightmare with an aluminum post in a carbon frame. What about 'liquid wrench' or any of those penetrating oils?

    I'm confused on the steaming process... how do you get steam where you need it? And how does it help?
    You have no excuse for driving to work
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  3. #3
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    Ammonia dissolves aluminum oxide, as does Kroil. Both can be dripped into the seatpost from a water bottle bolt hole, or in the seat tube via the bottom bracket shell. Plug anything it might exit from (the top of the seatpost, for example) and drop in about 500-750ml, leaving it to sit for 24 hours. Give it a twist, and it should come out. Otherwise, lop the top of the post off, and use a hacksaw blade taped at one end and cut a slit in the seatpost. Using a pair of channel locks, curl it up and pull it out.

    Always grease your seatpost when you do an overhaul on the bike--what happened is a completely preventable occurrence.

  4. #4
    weirdo
    Reputation: rodar y rodar's Avatar
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    I guess I`ve been lucky not to experience the pleasure of a stuck seatpost. It sounds like they can be a real nightmare. Glad you got yours out, Jeff.

    Quote Originally Posted by wschruba View Post
    Ammonia dissolves aluminum oxide, as does Kroil.
    I`ve heard of using amonia, but didn`t know why. Thanks for the explanation.
    Recalculating....

  5. #5
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    Quote Originally Posted by CommuterBoy View Post
    Are the frame and post both aluminum? I've heard that's a real nightmare with an aluminum post in a carbon frame. What about 'liquid wrench' or any of those penetrating oils?

    I'm confused on the steaming process... how do you get steam where you need it? And how does it help?
    Yup aluminium vs aluminium.....Tried Carb cleaner cause I haad some that is a pretty aggressive sovent also tried WD-40, just what I had on hand...

    I laid the bike on its side and put the kettle underneath where the top tube joins the seat tube...

    It really was the only thing that got any movement at all...

    I think it worked because the steam warmed the seat tube and made it larger...aluminium oxide is not a great conductor of heat....I also put some ice cubes on the seat tube (don't really think this helped much)...

    Just the small change in dimensions seemed to break the grip on the shaft....after about 2 minutes the thing would set up solid again so I would re steam it and wrestle some more....

    The major galling on the seat tube occurred at the bottom of the seat tube so I didn't even get the steam where it would have had the best effect...but it worked...

    I was very reluctant to pull out my propane torch because over heating the aluminium would cause it to harden and perhaps overhearden....that is become harder with no increase in strenght....ie get brittle...

    Of course I could have also melted the damn thing withe torch.

  6. #6
    weirdo
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    I can believe that. We heat bearings to 235F and slide them right onto a shaft by hand (gloved hand). Within about 15 seconds, the shaft sinks the heat out of the inner race and the bearing shrinks back down to size, won`t come off without a press or a hammer.
    Recalculating....

  7. #7
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    While preventable the thing was greased to hell and back last October prior to the long cold salty winter...

    I wash the bike probably four times over a six month winter....didn't pull out the seat tube...

    This is the first time in 8 years that the seat tube has frozen in....preventing the problem will require that I remove the seat tube clean and regrease say in Feb...

  8. #8
    sheep in FOX clothing
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    No issues in quite a few winters with little to no grease added... the possible difference being that I fiddle with the seat height at least a few times over the course of most winters like you do in the summer.

    That might be enough to do it.

  9. #9
    I Ride for Donuts
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    Another win for the high desert. We get plenty of snow...but no salt on the roads, and an average relative humidity in the single digits. I just pulled the post out of my steel Surly (which I did not coat, treat, or 'framesave') for the post-winter cleaning, and it looks brand new in there.
    You have no excuse for driving to work
    (unless you don't have studded tires)
    (no excuse for that either)

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