Seized seat post, opinions needed.

Teshu
Teshu Posts: 28
edited January 2010 in Workshop
Hi

I've been reading round the site for a while but not posted. However I now need some advice. I've got a seized seat post and without removing it my groupset upgrade is probbaly going to be pointless.
I inherited my dad's bike and it's sat for well over a year in a dry cellar, it's all in good condition except for the seat post which has seized. It's not a bad bike, was made to measure for my dad and is 531 tubing with shimano 105 groupset. It's a fair few years old but still a good bike with some sentimental value to me. Plus I can't really afford a new frame right now.

So I've removed the bottom bracket left it upside down and poured coke down it to start then I've tried penetrating oil, then plus gas specifically over a couple of days plus I've wacked it some. It's now hung upside down with 20kilos hanging off the seat post will leave this overnight.

I don't reckon it'll move though.
So should I saw the top off the seat post and then saw into the seat post and try to free it that way or apply heat via a small blow torch and see if that frees it? bit worried about heat as it'll ruin the paint and then what - respray?

Any thoughts apreciated.

Cheers Alex

Comments

  • My two pennorth for what it,s worth.

    Why the coke for goodness sake ? Can only see this worsening your probs and leaving a sticky sugary goo behind and improving your rust layer.

    Not mentioned in OP but assuming steel or ally alloy stem.

    1. Try to tap stem into downtube using block of wood on top of seatpost and hitting with a STEEL HAMMER using firm but not heavy blows. BB will need supporting on a rag say on a lump of wood, too heavy blows could ruin BB.

    2. If it moves slightly in with a chance. Put saddle back on spray top of seatpost/frame with plusgas or similar, reapply after say 10 min. Holding frame between knees twist saddle left/right and try to rotate a full turn or near on. Then twist side to side and pull if lucky wiil gradually work itself out.

    3. Will be virtually impossible to saw down inside of tube as prob too much tube inside . Even if you did would have to do it twice and attempt to knock down out of reach of new post. IMHO not worth considering.
  • Teshu
    Teshu Posts: 28
    I tried coke as it's acidic and I'd read that it may work- It didn't. I've seen coke clean all sorts of metal though.

    I'll try banging it again tommorow.

    I'd seen sheldon brown's page and this is were my saw idea is from

    "If nothing else works, the final resort is the old hacksaw blade trick. Cut the seatpost off so that about 1/2" is left sticking out, then insert a hacksaw blade into the seatpost and carefully cut a slit in the post. This is very laborious, and you run the risk of damaging the frame if you cut too far, but this approach cannot fail. Once you have cut the slit, grab one edge of the cut with a locking plier and roll the seatpost up inside itself and pull it out."

    I thought that this would be prefrable to using a propane torch, although I don't know how hot it would get and what it'd do to the finish.
  • LeighB
    LeighB Posts: 326
    Patience, keep squirting with WD40 and or penetrating oil and trying to move the post. I had one like this and it took a week but eventually came out. For a bit of extra leverage try putting the post in a vice and the frame gives you a bit more leverage but don’t go wild as it is very possible to bend the frame.
  • balthazar
    balthazar Posts: 1,565
    The saw method does work, probably infallibly, but it demands enormous care. Take lots of time, use a new hacksaw blade, stop for a break when you start rushing. It's only your time being spent. I did something similar recently – only it was to remove a car exhaust, so I was on my back in a garage, sawing a rusty mess 6 inches above my face, for about 3 hours. A seatpost job would have been a holiday in comparison..!
  • Teshu
    Teshu Posts: 28
    Found this on a site too -
    Best safe solution is take a hacksaw blade and cut the post down the inside cutting a small slot the crush the post that will break the crousion and make it easier to remove or cut ti into slices this process take a while but is safe and easy

    Think I'll keep going with the penatrating oil and get a hacksaw ready.

    I don't think there's loads in there as I can see all the fluting and a third of an inch of post too.

    I'm off to B&Q tommorow so I'll find a nice saw, think by wednesday I'll be ready to saw. twisted my ankle last wednesday so not been out for a good week now :(
  • elcani
    elcani Posts: 280
    I successfully removed an alloy seatpost (is your's alloy?) from a steel frame by repeatedly injecting household ammonia into the scalloped cut-outs on the post, then clamping the seat (or possibly seatpost clamp, can't remember) into a bench vice and twisting the frame (gently!).

    As you've got the bottom bracket out, I'd pour ammonia into that (as you did with the coke) and leave it for a while, then use a vice. If that works you'll save yourself a load of grief with the hacksaw.

    Cheers
  • Teshu
    Teshu Posts: 28
    I'm 99% sure it's a steel post in a steel frame so the ammonia won't work. I'd heard amonia works well with aluminum and steel bonds.

    I've sprayed loads of penetrating oil in via the bottom bracket hole but so far no joy. I'm hoping for a large crash in the night signifying the wieghts have pulled it free, think this is unlikley though.

    It's trying to balance patience with the chance that it may never come free with out destructive measures that's really annoying me, I just want to strip it down and put my new groupset on.

    Thanks for the advice so far, any thoughts and hints gratefully recieved.
  • lae
    lae Posts: 555
    Tried heating the frame with a blowtorch?

    Also Duck Oil is by far the best penetrating oil I've ever used (and I drive classic cars so I know a lot about rust!)
  • mmacavity
    mmacavity Posts: 781
    Freezing the seat pillar can sometimes work.
    Use liquid nitrogen, carbon dioxide fire extinguisher, Loctite Freeze&release, Sol-x freeze eaze, Kimball Midwest, Ambersill Rust etc etc. to freeze the seat pillar (shrink it just enough) then put seatpillar in a vise (bike/frame upside down) and brute force to remove seatpillar.
  • Teshu
    Teshu Posts: 28
    Started sawing last night :roll:

    I then discovered that I had an aluminum seat post :shock:

    So I sawed into it a bit and started trying to squish it in, this opened very small gap round some of the seat post and the down tube. Taking hours and a can of plus gas and many hacksaw and padsaw blades.

    So with a bit of research today I've bought caustic soda, and have discovered that it will dissolve aluminum. Unfortunatley as I'd cut the top off my post it means that the soda runs through so I'm waiting for some silicone to set around it forming a seal and then will poor in the caustic soda and wait for it to eat the post away.

    On the upside today my new front mech arrived today and the band fit's my frame! Hooray.

    Now it's fingers crossed the post dissolves OK.
  • sturmey
    sturmey Posts: 964
    So with a bit of research today I've bought caustic soda, and have discovered that it will dissolve aluminum

    I like your style.
    If it won't come out, dissolve it!

    Bit drastic I would say
  • Teshu
    Teshu Posts: 28
    sturmey wrote:
    So with a bit of research today I've bought caustic soda, and have discovered that it will dissolve aluminum

    I like your style.
    If it won't come out, dissolve it!

    Bit drastic I would say

    To be honest I'm a tad impatient now I've had 4 days off work and it's still stuck firm, and the only thing that will realy do it without major frame damage seams to be this. I could try heat but I reckon that'll really ruin the paint and I don't think it works with aluminum steal bonds.

    At least this way I'll end up with relativley small damage to my paint and just at the top of the tube and a clean inside of the tube. IS THE PLAN!
  • Saw it, alloy is softer than steel, you`ll know when you`ve gone through the alloy and are into the steel. Patience will sort it, rushing it will wreck your beloved frame :cry:
    Jens says "Shut up legs !! "

    Specialized S-Works SaxoBank SL4 Tarmac Di2
  • sturmey
    sturmey Posts: 964
    Saw it, alloy is softer than steel

    +1

    If you buy a decent quality 'Eclipse' 300mm hacksaw blade ,18 or 24 tpi, you will have enough length and cutting power to get through it- failry easily in fact.
    I have had to saw through 28mm copper pipes using a bare blade many times and it is not the hardest job in the world.

    Hold the blade in a cloth and take your time.
  • Teshu
    Teshu Posts: 28
    I've been sawing and I can see that it's fairly soft for metal but that still leaves me needing to use some brute force and tension on the frame to remove parts of the stem from the tube and I think it's been stuck for some time forming a bond. I don't reckon the seat post has been adjusted in a good 4 years.

    The steel should be unaffected by the soda and I can still saw some when it's eaten some stem away. THe soda can work while I'm at work and I can saw at night.
  • elcani
    elcani Posts: 280
    Ammonia.
  • Saw a slot, crush the tube in on itself with some mole-grips, the bond isn`t that good, it won`t have welded itself to the steel. Messing about with chemicals etc is just asking for trouble and a visit to A&E to have yer eye washed out :shock: that`s without it affecting anything else it comes into contact with on the bike, like paint and other alloy components. I`tll take you half an hour with a blade :?
    Jens says "Shut up legs !! "

    Specialized S-Works SaxoBank SL4 Tarmac Di2
  • Wappygixer
    Wappygixer Posts: 1,396
    Before I got to your post I was going to recommend caustic soda.It will disolve the alloy over night.I've had friends clean motorcycle engine parts in this, left it over night come back next morning and all parts are gone.
    It wont do any damage to your frame but it may strip the paint it comes into contact with.

    I've been where you are a couple of times with the sawing method.Very sore fingers, lots of swearing but they do come eventually.
    Keep us updated.