Removing a very stuck seatpost

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  • Removing a very stuck seatpost
  • tinsy
    Member

    Is shock & unlock like the plumbers pipe freezing kit stuff? Maybe the plumbing stuff would work?

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    Hacksaw the top off, then cut slivers into the remaining tube. It’s a long process that should work

    brakes
    Member

    crush seatpost in vice and twist the frame?

    organic355
    Member

    Hacksaw the top off, then cut slivers into the remaining tube. It’s a long process that should work

    THIS

    had to do this with a carbon post stuck in an allow frame, then peeled, filed, scraped out the bits.

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    This may help.

    It’s an old post of mine when I had the same problem.
    It’s free and with a try 🙂

    Tried that with a bench vice, naddda, no movement at all, the frame would probably give way first!

    luddite
    Member

    I have had good results with diesel, old boy recommended it, nasty stuff.
    Pour it in and leave over night and try the vice again.

    allthepies
    Member

    crimp the seatpost a few cm up from the frame using a vice.
    turn frame upside down
    pour caustic through BB shell into seat tube until seattube full
    leave alone for caustic to do its thing

    robinlaidlaw
    Member

    Hacksaw the top off, then cut slivers into the remaining tube. It’s a long process that should work

    Another +1 for this.
    I’ve been involved in removing a few in my bike mechanic days and this will always get it out in the end but it’ll take a while and you need to be careful.

    TiRed
    Member

    Hacksaw the top off, then cut slivers into the remaining tube. It’s a long process that should work

    Did this, but it doesn’t ALWAYS come out in the end. Eventually, I think I lost patience and when it started to move, just pushed it further in.

    I’d go chemical attack first.

    Grizla
    Member

    I’ve done the caustic method.

    Fixed frame upside down and squirted it through bottle cage braze ons with a syringe, left BB etc installed.

    It’s a long process, you’ll need to change the solution a few times. It’ll perhaps make a mess of your paint too. In hindsight I don’t know whether or not it was preferable to slicing it from inside with a hacksaw blade.

    Edit: Also, concentrated Sodium Hydroxide isn’t nice stuff.

    Edric 64
    Member

    Argos cycles just torched the one out of an 853 inbred I bought cheap

    robinlaidlaw
    Member

    Did this, but it doesn’t ALWAYS come out in the end. Eventually, I think I lost patience and when it started to move, just pushed it further in.

    The way we used to approach it was to start out with the usual stuff and then once it became clear that you weren’t removing the post alive, we’d drill a big hole straight across the post not too far above the frame and install a 1/2″ stud and nuts through that. Then absolutely soak it in penetrating lube and try gripping the post in a bench vice (the stud / nuts stops it twisting) and use several people to try to turn the frame. If that doesn’t work you split it with a hacksaw blade, usually just one slot is enough and if it doesn’t come out easily at that point you go back to the vice and penetrating lube. Once it’s split, the gripping the post in a vice and twisting the frame will get it out every time, albeit sometimes accompanied by horrible creaking noises.

    Finally got to the Chas Roberts in the garage last weekend, tried three or four times with heating (propane) nothing doing swinging on it with a pair of Stillsons three of us holding the frame etc.

    Then tried heat once more, but cooled very quickly from hot with a couple of gallons of water, Pop she went by this point the 2′ stillsons had an old manipoo 1.5inch fork as an extension bar on. When I say pop I mean it move 5deg round. There was some seroius force on it. another hours of pulling the Stillsons round with the bar on (adding gt85) and she started to lift up.

    **edit all heat applied to the frame around the lug but not to the point of melting the bronze

    LBS has tried and failed, so no ammount of plus gas, shock’n’unlock (which is nowhere near as cold as I remember it being, changed recipie?) or bench vices are going to help.

    Frame is a Ron Cooper road frame, lugges and Columbus steel tubing (basic CrMo though, nothing fancy)

    Options:

    a) heat, applied to the seatpost untill it’s close to melting to break the bond with the frame? Would try the frame but woried I’d melt the bronze and not wanting to try twisting it while it’d hot.

    b) chemicals? Caustic should dissolve aluminium, but how to keep it in the frame untill all traces of aluminium are removed? I’ve not got a big enough tank or enough caustic to dip the whole thing! Ammonia should work too, but a bit more unplesant and the same issues?

    c) crush the seatpost in a vice just above the clamp and hope ti pulls away from the seatube rather than crack?

    d)?????????

    Dibbs
    Member

    There was a video of the caustic soda method on here the other week, it looked like dangerous fun 🙂

    robinlaidlaw
    Member

    Heating doesn’t usually work in this case, aluminium expands more than steel. It can be useful for steel parts stuck in alloy frames though.

    bencooper
    Member

    I’ve tried all those ways, plus using expanding reamers to bore it out – the cut in to slices way is the best I’ve found in general. Do two cuts, 30 degrees apart, use a long flatblade to pry out the wedge, then crush the seatpost in a vice and twist.

    bigsurfer
    Member

    I did the caustic soda a couple of months ago and it worked perfectly after a 3 day soak.

    Mix the caustic soda to paint stripping concentration and pour it into the upside down frame via the bottle mounts if you have some if not remove the bottom bracket. I used a small piece of tube and a little funnel.

    Leave to soak mine took 3 days after which you could see a small amount of caustic soda had made it past the seat post. I put it in a vice and with a bit of brute force it came free.

    My cautionary tale regards where the caustic soda ends up as I killed a good patch of the grass on our lawn emptying it out, washed it away with the hose pipe as soon as I spilt it but it has still killed the grass.

    Premier Icon leffeboy
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    The bencooper method has worked well for me

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