Stuck seatpost. And I mean stuck!

[Yog Sothoth]

My 91 Alpinestars cromega seatpost finally bit the dust last week, the clamp completely giving way. The saddle had been slipping for a while as the serrations on the clamp were smoothed off. Repeated retightening had effectively stripped the threads.

The post was well tatty anyway, and was the original post from new.

I expected it to be somewhat seized, as that's how it was when I got the bike off ebay. However, no amount of whacking with mallets and escalating sizes of hammer has budged it 1mm. Nor has clampintg it in a vice and turning the frame - all that did was deform the post.

I've given it three soakings in 10% sodium hydroxide, poured down the seat tube. The last of these was over 2 days. Still no movement.

By this time, the seatpost was so badly damaged I had to saw it off. Only thing I have left is a hacksaw blade, but that is a thick seatpost and the seat tube is so thin! I sense disaster and a present for the prowling pikey scrap thieves.

Anyone any other suggestions? And has anyone any tips for sawing a post out?!

 

[tonedeaf101]

Shame you cut it off, could have put some blow lamp action on it, may have cracked the corrosion a bit. Wouldnt put it on the frame though unless you are planning to repaint it afterwards.

 

[bm0p700f]

Plus gas applied every day twice a day for as long as it takes to free the ting works. Clamping the seat clamp in a vice and turning the frame should eventually free, LGF has a nmenthod that involves a quill stem and handle bars. Patience for really stuck post is needed. That or conc. NaOH or a welding torch to melt it out.

Try the plus gas method. It took weeks to get a very siezed campag seatpost out of a steel carlton using plus gas. It shift in the end though.

 

[Yog Sothoth]

OK, what is plusgas and where can I buy it?

 

[Yog Sothoth]

I tried the conc NaOH btw, 3 times so far!
And clamping in a vice and turning the frame. The frame will bend before the post moves!

There's about 7 inches of the post stuck inside the seat tube.

 

[unkleGsif]

Google PlusGas to see what it is and where you can get it, but every good motor factors should have it.... however it will be pretty useless now youve cut the seatpost off, as even if you do manage to loosen it, you cant grab it now to turn it out

Therefore, your only option is to keep going with the caustic soda, it will work in the end.... go stronger than 10%.... go to 2:1 water:soda

http://www.youtube.com/watch?v=-dYnSVVDxrE&feature=related
This has been posted several times on here before, and there is a chap on here (with a green kona) that did something similar. I recall it took him several attempts

plug the frame up, so that you can fill the seat tube and it will be quicker


G

 

[Yog Sothoth]

OK. I'll have to get back on ebay for some more NaOH! Cheers.

 

[Rampage]

OK. I'll have to get back on ebay for some more NaOH! Cheers.

http://apcpure.com/products.php?product=112

 

[mikede]

You guys have 'PB Blaster' over there in the auto-parts stores??

 

[harleysteve08]

If you CAREFULLY cut 2 saw cuts 5 -10 mm apart down the tube with a hacksaw blade taking care to stop before you reach the seat tube, you can then peel this away to leave the stuck tube with a section missing. This will allow room for what's left of the post to reduce in diameter, soak it well too with some penetrating oil and it should move. Never had one yet that doesn't surrender under this method, good luck.