My uncle just gave me his old steel centurion and the seat post is stuck. Any solution?

Lots of penetrating oil to top and the next day to the bottom of the seat post by taking the cranks and BB off/out. Move the seat as far forward on the rails as possible and use the saddle nose to apply torque.
You can apply a lot of torque this way. Next step after a week or two of repeated soakings and trials would be to clamp the seat in something, a slot the width or a bit less of the seat with the bike upside down and use the frame to torque the seat. Either the seat clamp will give/break or the post will loosen and you will be able to wiggle it off. If the clamp breaks then it gets complicated. Is the post steel also?
If the saddle rails break or come loose cheap saddles are probably available throwaway at the LBS for further efforts. Steve

Along with oil on the top, rather than taking the BB off, unscrew the little water bottle bolts, flip the bike upside-down, and spray WD-40 (with the little red straw WD-40 cans usually come with) in the holes. Then do as above with the seat after a few days of this (leaving it to sit overnight). Perhaps use a crap old seat to avoid bending the rails on the one you intend to actually use.

Here's 15
https://www.sheldonbrown.com/stuck-seatposts.html

Sheldon has a ton of solutions: 15 Ways to Unstick a Seatpost

Including:

Diagnosis
Before you get serious about a stuck seatpost, you should find why it is stuck. There are two possible reasons: The seatpost may be stuck mechanically, for instance by being the wrong size and having been forced in; or, the problem may be chemical, caused by corrosion.

# 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.

If nothing else works, the final resort is the old hacksaw blade trick.

Hey!

https://secure.cnchost.com/kanolabs....m#anchor173855

Thanks for the reply, but how do I tell if the seat post is aluminum or steel?

magnet.


Good luck with this. I have two bikes with stuck seatposts, and I've tried everything, esp. lots of ammonia, PBlaster and Liquid Wrench. Nothing's worked so far.

I think the bb is a good place to go in, too--many nice, older bikes don't have the bottle cage mounts on the seattube.

I agree with the above suggestions to read the section on Sheldon Brown's site regarding stuck seatposts.........I had just such a problem recently, coincidentally, with an old Centurion, too. What I do to solve the problem, and it's always worked for me, is this: first use very lightweight penetrating oil in the seat tube, both from the top and bottom sides if possible. Let soak at least overnight. Then take an old, junker saddle that you care absolutely nothing about and install it on the seatpost. Take a hammer, and at first with moderate force, begin hitting the forward portion of the junker saddle. If you feel the seatpost move, problem solved, just move to the other side, hit it another time or two to move it a little more, and at this point you should be able to straddle the bike and remove the post by hand. If it doesn't move after the first series of moderate blows, increase the force you hit it with, moving from one side to the other after every few blows. If it's stuck so badly that it won't budge using this method, it's probably time to use some of the more extreme measures listed on Sheldon's site. I will say that I've had to beat the crap out of an old junker saddle to get it done, but I've been fortunate in that I've always been able to free a stuck post using this method. There are worse cases than what I've dealt with, I'm sure, but the good thing about this method is that if it works, the only thing you've damaged is the old junker saddle, because you're striking it forward of the clamp area on the post. Good luck-

I have a few bikes I also seem to have no hope removing the stuck posts, I am certain they are steel, however its hard to soak them in oil when they are hollowed out.. I need to find some way to "plug/cork" the seat post so the oil doesnt just leak out when the bike is sitting upside down. Removing stuck neck stems is no big deal as the stem itself blocks any of the oil from leaking out!

All other stuck seat posts Id attack with some oil though at the top, and using a monkey wrench to twist the post to free it. The wrench leaves deep claw marks all over the post, but its worked for me about 4 times out of 7 or so!

I just had one of these the other day. Liquid wrench for 2 days around the seat post. Crescent wrench on the top of the seat post. Moved it side to side a couple of times and came loose. Sure there is a scratch on the seat post now, but what do you expect.

This worked for me on two different seat posts. First, let penetrating oil soak in for a few days. If the frame is stripped, or at least the bars, wheels and pedals or cranks off, so you can lay the bike flat on the garage floor or drive, put the biggest crescent wrench you can find on the flats on the top of the seatpost.

STOMP HARD!! It may take a couple of stomps, but in both cases a good hard stomp did the job.