Seat post stuck

Discussion in 'Motorized Bicycle General Discussion' started by \./, Mar 24, 2013.

  1. \./

    \./ Member

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    That sounds good In theory but I just don't see it working in practice. There's noway I can put enough pressure to cut through it while the saw is Inside. This tube is less than 7/8" in diameters and roughly 8-9" long
     
  2. Toadmund

    Toadmund New Member

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    Sodium Hydroxide
    One of the ideas here
    Hopefully your frame is steel.(which it looks like) You said your tube was aluminum, right?
     
  3. \./

    \./ Member

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    I'm gonna have to do something drastic like a chemical treatment. The aluminum pipe isn't just siezed, it was literary hammered in till it wouldn't go in any more...
     
  4. Toadmund

    Toadmund New Member

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    Plug'er off and fill'er up!
    (outdoors)
    Maybe you could fill it with drano crystals, then put in some water.

    And at least protect your eyes, and a raincoat and waterproof gloves or something.
    You don't want drano on your skin or in your eyes.

    Let us know how you made out.
     
  5. Maxvision

    Maxvision New Member

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    Good Ol' Muriatic Acid (same stuff you put in swimming pools and can get at any hardware store) is pretty aggressive w/ aluminum, will take away a lot more aluminum than it will the iron. Need to dilute it maybe 25% acid, 75% water (always pour the acid in the water, not the other way around).

    Will have to pull your pedal crank and bearings and block the tube off from the bottom. Leave it in for about an hour and give it a try. I left some iron in some acid mix on a Friday and on Monday the iron was gone so don't forget about it.

    Muriatic acid also does a decent job etching metal before painting too. Gives the metal a bit more "stickability" for the paint than just sand paper. After I sand off the old paint I'll use a brush to paint on some acid and just leave it till it dries then paint over it.
     
    #25 Maxvision, Mar 25, 2013
    Last edited: Mar 25, 2013
  6. \./

    \./ Member

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    Way too much hassle for what it's worth. I think I'll just cut the tip off and weld a front seat mount and use some seat springs in the back
     
  7. crassius

    crassius Well-Known Member

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    I had one of these once. Was able to cut it flush with top of bike frame, cut a slice in it where the frame tightening slit was, and put a much smaller diameter post inside it - done.
     
  8. \./

    \./ Member

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    So here is the bike...
     

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  9. Toadmund

    Toadmund New Member

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    At what point does a motorbicycle become a motorcycle?
    COOL!
    I'd get a seat on that. (for comforts sake)
    I assume you are going with crassius's idea.
     
  10. \./

    \./ Member

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    I'd really much rather get that damn aluminum tube out, buy I honestly do not see it coming out with what I have to work with. I'm gonna do a btr type of a seat
     
  11. \./

    \./ Member

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    Sorry to disappoint you fellas, but there's absolutely no way this thing is coming out... Turns out its not aluminum like I thought. :(
     

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  12. Maxvision

    Maxvision New Member

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    Well Yuri, you know where you can come to get what you need to get that thing out! Over here at my house.
     
  13. maniac57

    maniac57 Old, Fat, and still faster than you

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    Weld a thick chunk of steel to it and pound it out. Add another pipe to the top if needed to get serious with a sledgehammer and it WILL come out.
    Get medieval on it!
    You could also cut the slit in the seatpost tube longer to relieve some of the grip if you can get down to where the problem is with out going nuts. I wouldn't extend the slit more than a inch or so.
     
  14. \./

    \./ Member

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    I doubt this bike will fit into my little coupe lol (I drive a scion tc)
    I'm gonna give it 1 more go before calling quits
     
  15. Legwon

    Legwon New Member

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    thats what bike racks are for :p
     
  16. \./

    \./ Member

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    zpt
    This isn't an ordinary bike... Any rack you can attach to the back of a coupe won't be strong enough to hold the bike...
     
  17. glennbo

    glennbo Member

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    i once had this problem someone pounded the wrong size seat post in with a sledge hammer it was so tight it split the down tube the way i got it out was i used a 1 inch hole saw and cut a hole in the bottom bracket got a long piece of 5/8 bar and beat the sob right back out! brazed the split in the tube and the round plug back in the bottom bracket. its a little extreem but the frame was an old schwinn so i wanted to save it!!
     
  18. maniac57

    maniac57 Old, Fat, and still faster than you

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    Great idea if nothing else works. Looks to me like the bike is worth saving too.
     
  19. MEASURE TWICE

    MEASURE TWICE Active Member

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    I think if aside of all the ideas and of course also getting a mill and jigging it up to take out just the post, maybe leaving it in. What I mean is using it in some way to clamp something that post sticking out. Then laterally forward or aft have a metal connection that has another seat post that can move a small amount up or down. Kind of analogous to those lay back seat post setups.

    It may not be what you want or have room to work, but maybe?

    If cutting out the frame portion and welding back in a new section can be done by you or economically some how, throwing out the frame would not be necessary. I've welded a bit, but not brazed or used a torch. My MIG has some limitations.

    MT
     
  20. CTripps

    CTripps Active Member

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    Is there any way you can secure the bike to something solid (straps around a tree or something) and then hook on to that post and use something else to pull on the post? I'm thinking of somethine like a ratcheting tie-down strap, or winch, engine hoist.. tow cable to a hitch.. anything? As long as you can hold the bike still and pull on the post, there's got to be a way.
     

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