Bicycle Mechanics - Seatpost is stuck

I received a used pain-in-the-@ss mountain bike that needed an entire overhaul. Oh, why did I even bother?....

Anyway, the final step is the seat-post. It is stuck like Lucifer in hell. I have tried absolutely everything; lubricating oil, heat, placing the seat post in a vice - the works.

The problem is that some IDIOT pounded the too-big seat post into the post tube (Don't ever do this). The post tube has a slight tell-tale bulge.

Anyway, it isn't coming out. No way.

The OD of the seat tube is 27.7 mm. What can I do? Can I cut the tube off, cut a slit along the post-tube slit, and insert another tube? Is this practical?

Are there tubes I can buy that will go over the 27.7 mm tube?

If you have been through this yourself, you know the frustration.

Sorry about that, Mike! Is the seat post aluminum or steel? Have you tried running a drill bit or hacksaw blade parallel to its axis, to cut a groove down the post? Your bike's previous owner is what we used to call a ZMA (Zero Mechanical Aptitude) at Bikecology/Supergo. If you ever do get that post out of there, be sure to check the seat tube and seat stay cluster for cracks.

Cut the seat post off to the frame, and duct tape a bath towel over it......voila you've got a seat! LOL

I never had it that bad, but it will come out. I think the hacksaw idea is your ace in the hole.

Did you pick up the Schwinn or the Giant?

yea is that the schwinn or giant?

Have you tried smacking it with a large hammer? You might drive it in slightly farther, but it might break it loose if it is gaulded(sp?) to the tube. Just a thought.

Turn the bike upside down and pour some anti-freeze down into the tube and and let it soak for a while. If you think this is radical, I agree, and old-time frame bulider told me about it and I haven't had to try it yet. I've done the same with penetrating oil and done OK, so far.

Ride Free
Pat

Mike,
How far into the seat tube is the post inserted? One near-last-resort measure that might be a possibility is to cut the top off the seatpost (if necessary) and try to use a hacksaw blade from the inside to cut a slot in the post. It would take a while, but it might work without further damage to the seat tube. You could start the slot in the exposed part with a Dremel tool and emery discs, leaving only the inserted part for the hard sawing. I would leave 2-3 inches of seat post exposed to allow for other efforts if this proves impractical.

A machine shop might have tools for getting things apart. If you know someone they might even do it free.
Good luck,
Raymond

Originally posted by John E
Sorry about that, Mike! Is the seat post aluminum or steel

The frame and the seat-post are steel. John brings up an important point here, folks. An aluminum post in a steel frame will weld together over time to the point that it is almost impossible to get out.

Sheldon Brown (Cool Sheldon) on his "15 ways to remove a stuck seat-post" site recommends using ammonia on aluminum oxide. He says it just washes away the oxidation.

Originally posted by Oscar
I never had it that bad, but it will come out. I think the hacksaw idea is your ace in the hole.

Did you pick up the Schwinn or the Giant?

Actually, it is the Giant, but I am going to get the Schwinn too. I can't pass up the Schwinn - Schwinn's are in my blood.

Originally posted by Dirtgrinder
Have you tried smacking it with a large hammer? You might drive it in slightly farther, but it might break it loose if it is gaulded(sp?) to the tube. Just a thought.

Yup, I tried the hammer idea. It wouldn't move. That is when I noticed the bulge in the frame and realized that some ZMA (As JohnE identifies above) pounded the post into the frame.

Originally posted by RainmanP
Mike,
How far into the seat tube is the post inserted? One near-last-resort measure that might be a possibility is to cut the top off the seatpost (if necessary) and try to use a hacksaw blade from the inside to cut a slot in the post.
Raymond

Ya, this is the "last resort" which Sheldon mentions at his site.

inserting a hack-saw blade into the tube and manually trying to cut it vertically seems like it would take about 3 years with a hack-saw blade give or take six months. Maybe if I was stranded on a deserted island with nothing else to do this would seem more appealing.

Mike, with a course blade (18t) you should be able to do it in less than an hour.

Well, guys, here is what I did - and it worked famously;

I cut off the stuck post except for about 2" - leaving room for the next ambitious owner who might want to try his/her hand at getting the seat-post out.

Then, using a drill mounted disc cutter, I sliced the stuck seat-post vertically along the tension-slit in the post-tube.

Then, I slipped a smaller diameter seat-post inside the stuck post.

The new seat-post O.D. was almost the same diameter as the stuck post I.D.

With a shim, it fits pretty well. I rode the bike to work today and all is well thus far.

That was silly. I spent three days rebuilding the whole bike, replacing parts, and doing paint touch-up. When I went to give it a test ride, I discovered the seat post was helplessly stuck.

Next time, I'll check the seat-post first.

Remember, Folks:

1) NEVER EVER pound a seat-post into a post-tube.

2) Be sure your post-tube has a thin coat of grease to protect it from corroding to the seat post.

You might want to try to cut the post and leave appox 3" above the seat tube. I have an automotive errentic tool that fits into the post and if it grabs it would turn the post.
Or you can cut the post on the inside and remove a peice of it. This would lessen the pressure to try and remove it.

If you do decide to cut it out an electric jigsaw with a long metal cutting blade could cut the inside of the post in fairly short order.

Try drilling a hole crossways and then you could insert a pin. Tapping with a hammer might just loosen the bar, otherwise fit the whole caboosh in a mighty vise and try twisting the frame...
It's an idea

R

Originally posted by Harry
Try drilling a hole crossways and then you could insert a pin. Tapping with a hammer might just loosen the bar, otherwise fit the whole caboosh in a mighty vise and try twisting the frame...
It's an idea

R

Ya, I tried that too. It didn't work.

Sheldon Brown brings up a good point in his "15 ways to remove a stuck seat post". He recommends not turning posts that have been pounded into the seat tube because it could act like a cam and make it even more stuck than before.

I got my stuck seatpost out on Sunday while watching the football game. I cut the post off about an inch above the top of the seat tube. then using a hacksaw blade held in my hands, I cut the tube inside lengthwise. It took a little over half an hour and was much easier than I thought it would be.