Stuck seat post-Help!

[Stuart Jenkins]

I have possibly a not uncommon problem. Having neglected my girlfriends steel Kona lava Dome the seat post (aluminium I guess) is siezed solid. Tried heat, WD40, hammer and lots of brute force. Any miracle suggestions?

Local bike shop suggested some kind of 'acid' placed in top of seatpost and then inverting the bike to let it seep in between the steel frame and aluminium seat post. . Sounds a bit extreme but I have little options left. The seat post is siezed in a too high position. The bike shop didn't know what kind of acid!

Cheers Stuart

 

[boudreaux]

I have possibly a not uncommon problem. Having neglected my girlfriends steel Kona lava Dome the seat post (aluminium I guess) is siezed solid. Tried heat, WD40, hammer and lots of brute force. Any miracle suggestions?

Local bike shop suggested some kind of 'acid' placed in top of seatpost and then inverting the bike to let it seep in between the steel frame and aluminium seat post. . Sounds a bit extreme but I have little options left. The seat post is siezed in a too high position. The bike shop didn't know what kind of acid!

Cheers Stuart

Find another LBS not populated by morons. Sheldon Brown at www.harriscyclery.com has an article on stuck posts and the approved methods.

 

[Fat Hack]

This one?
http://www.sheldonbrown.com/stuck-seatposts.html


"Aluminum seatposts frequently become stuck by corrosion also, and penetrating oil is almost useless against aluminum oxide. Fortunately, aluminum oxide can be dissolved like magic by using ammonia. "

 

[Stuart Jenkins]

Thanks for that- I'll try some ammonia!

Stuart

 

[Fat Hack]

Thanks for that- I'll try some ammonia!

Stuart

That was just one of the more 'serious' tips. I'd recommend reading the whole article

 

[Doctor Morbius]

I have possibly a not uncommon problem. Having neglected my girlfriends steel Kona lava Dome the seat post (aluminium I guess) is siezed solid. Tried heat, WD40, hammer and lots of brute force. Any miracle suggestions?

Local bike shop suggested some kind of 'acid' placed in top of seatpost and then inverting the bike to let it seep in between the steel frame and aluminium seat post. . Sounds a bit extreme but I have little options left. The seat post is siezed in a too high position. The bike shop didn't know what kind of acid!

Cheers Stuart

ACID?!?!? What a bunch of tards!

 

[boudreaux]

ACID?!?!? What a bunch of tards!

Coke (in a bottle) is acid. Recommended for some stuck stuff. The LBS morons would have likely used battery acid tho.

 

[Doctor Morbius]

Coke (in a bottle) is acid. Recommended for some stuck stuff. The LBS morons would have likely used battery acid tho.

Muratic acid came to mind as I was reading. My Grandfather used to pour it down the pipes when there was a bad clog. Also good for cleaning the grill from time to time.

I can't imagine how a seatpost would get in that condition in the first place. Putting a thin film of grease on it when it is new is so easy. Wouldn't recommend it for carbon fiber seatposts though.

 

[Stuart Jenkins]

That was just one of the more 'serious' tips. I'd recommend reading the whole article

Yep - read the article- I'm at the more 'serious tips' stage having tried everything else!

 

[jhuskey]

Yep - read the article- I'm at the more 'serious tips' stage having tried everything else!

Carefully heat the post,not the frame, with a heat gun or better a small propane torch then twist.It is better to leave the seat on for leverage.

 

[Weisse Luft]

Carefully heat the post,not the frame, with a heat gun or better a small propane torch then twist.It is better to leave the seat on for leverage.

Probably will not work since aluminum expands more than steel.

If post is really stuck, remove seat, bottom bracket and bottle cage. Invert the bike in a bike stand and place a drip pan under the bicycle. With a turkey baster, fill the seat tube with the strongest ammonia you can find. It will take a while to dissolve but it will work.

I have had a seatpost so badly corroded even this trick didn't work. I finally dissolved the entire post using sodium hydroxide since the steel frame is passive to sodium hydroxide. Paint isn't so be careful.

 

[jhuskey]

Probably will not work since aluminum expands more than steel.

If post is really stuck, remove seat, bottom bracket and bottle cage. Invert the bike in a bike stand and place a drip pan under the bicycle. With a turkey baster, fill the seat tube with the strongest ammonia you can find. It will take a while to dissolve but it will work.

I have had a seatpost so badly corroded even this trick didn't work. I finally dissolved the entire post using sodium hydroxide since the steel frame is passive to sodium hydroxide. Paint isn't so be careful.

It actually has worked for me.

 

[phreak]

I had exactly the same problem

I was rebuilding the bike so the whole thing was stripped and i put the frame and stuck seatpost in the freezer.
because aluminium alloy has a greater coefficient of linear expansion than steel therefore expands more under elevated temperature so it also shrinks more in the cold too. once Id frozen my bike I tapped the post a few times and twisted out with a plumbers wrench

good luck

 

[jhuskey]

I had exactly the same problem

I was rebuilding the bike so the whole thing was stripped and i put the frame and stuck seatpost in the freezer.
because aluminium alloy has a greater coefficient of linear expansion than steel therefore expands more under elevated temperature so it also shrinks more in the cold too. once Id frozen my bike I tapped the post a few times and twisted out with a plumbers wrench

good luck

I didn't have freezer that big but used heat and a large wrench also to turn the post. Once you break the bond loose the post will wiggle out.
You could probably use a metal rod or rebar tightened down on the seat post for leverage.
I am not sure if the aluminium expands,breaks away and then shrinks but know that it can work with a torch.

 

[Caher]

Sorry to interupt but I'll be installing a new seat post at the weekend and thought if i greased it too heavily it would slip back down rather too easily!

 

[Fat Hack]

Sorry to interupt but I'll be installing a new seat post at the weekend and thought if i greased it too heavily it would slip back down rather too easily!

No, if it's the correct size, it shouldn't

 

[Powerful Pete]

You just need a thin film of grease covering the surface that will go into the frame. Do not go overboard with three kilos of glop!

 

[Andrews1]

What about carbon seatposts stuck in Ti frames.