Stuck seatpost in a bonded alloy frame
- Thread starter Excel
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Jonny69
Senior Retro Guru
I've had a few 979s but not with stuck seatposts. Couple of things you absolutely must not do:
-Do not force it by twisting because you'll risk damaging the bond at the seat cluster
-Do not use heat (hotter than boiling water) because you'll damage the adhesive at the seat cluster
-Do not prise the seat clamp open if it's one of the earlier frames - it will snap
-Do not use caustic soda because it'll dissolve the frame
I think time and patience are going to be your best friends. Take the Allen head grub screw that secures the seatpost all the way out the seat cluster if it's one of the later frames. Get a tin of Plus Gas and dribble it down the where the seatpost goes into the seat tube and basically let it sit. Check it after a few hours by giving it a wriggle and twist with an old saddle for leverage. Basically keep repeating that for as long as it takes (days/weeks)! Once it starts moving just keep working more Plus Gas or WD40 into it until it comes free. But what you definitely don't want to do is stick a big bar on the seatpost and use brute force!
-Do not force it by twisting because you'll risk damaging the bond at the seat cluster
-Do not use heat (hotter than boiling water) because you'll damage the adhesive at the seat cluster
-Do not prise the seat clamp open if it's one of the earlier frames - it will snap
-Do not use caustic soda because it'll dissolve the frame
I think time and patience are going to be your best friends. Take the Allen head grub screw that secures the seatpost all the way out the seat cluster if it's one of the later frames. Get a tin of Plus Gas and dribble it down the where the seatpost goes into the seat tube and basically let it sit. Check it after a few hours by giving it a wriggle and twist with an old saddle for leverage. Basically keep repeating that for as long as it takes (days/weeks)! Once it starts moving just keep working more Plus Gas or WD40 into it until it comes free. But what you definitely don't want to do is stick a big bar on the seatpost and use brute force!
Sir Neil d'Menture
Retro Guru
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You may find that the only way to remove it is with a hacksaw blade. Sorry.
jim haseltine
Retro Guru
That is often the only solution. I have had occasional success (like, er, twice out of lots and never tried it with an alloy frame) on stuck parts with a combination of plumber's pipe freezing kit and hot water.
Fit the kit foam jacket around the seat post so that it's just clear of the seat lug. Inject spray under the jacket following the instructions, wait 5 minutes and inject more spray, repeat until the whole can has been used. Wait 10 more minutes then check that the seat lug is cold - you might even see frost or ice forming on it - then put a cloth in hot water, wring it out and wrap it around the seat lug and tube. You may need to apply the cloth a number of times.
A lot will depend on whether you want the seat post in one piece and how quickly you want to move on. I can't remember if Vitus seat tubes are open to the BB shell (something is telling me that they aren't) but if it is and you're not pressed for time I'd hang the frame upside down over a drip tray somewhere out of the way, carefully fill the seat tube to some depth with diesel oil and leave it in the hope that it'll wick through. You may well need the agreement of your other half because it may need to be there some time and it'll stink.
Fit the kit foam jacket around the seat post so that it's just clear of the seat lug. Inject spray under the jacket following the instructions, wait 5 minutes and inject more spray, repeat until the whole can has been used. Wait 10 more minutes then check that the seat lug is cold - you might even see frost or ice forming on it - then put a cloth in hot water, wring it out and wrap it around the seat lug and tube. You may need to apply the cloth a number of times.
A lot will depend on whether you want the seat post in one piece and how quickly you want to move on. I can't remember if Vitus seat tubes are open to the BB shell (something is telling me that they aren't) but if it is and you're not pressed for time I'd hang the frame upside down over a drip tray somewhere out of the way, carefully fill the seat tube to some depth with diesel oil and leave it in the hope that it'll wick through. You may well need the agreement of your other half because it may need to be there some time and it'll stink.
Takingabreak
Dave Yates Fan
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Won’t the tube and post expand and contract with temperature at the same rate?
jim haseltine
Retro Guru
Very nearly but not quite as long as it's oxidization that's holding the pin in place because it has a slight insulating effect. The contraction/expansion should hopefully break the bond of the oxide. The lug doesn't need to expand much to loosen the post. There's always the chance it'll work but I wouldn't reccomend getting the spray anywhere near the bonding though.
Excel
Retro Guru
Thanks Jonny69 for your helpful reply, I've recently acquired the frame and didn't notice when purchasing a small crack under the seatpost binder bracket (it's the earlier version before they introduced the rear grub screw) would this make the frame a write off as I guess an alloy weld would compromise the bonding?
