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Stuck Seatpost After "Only" 30 years.

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Stuck Seatpost After "Only" 30 years.

Old 02-23-20, 12:32 PM
  #1  
Homebrew01
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Stuck Seatpost After "Only" 30 years.

Steel frame, aluminum seatpost. After soaking with Kroil for a while, I'm going to drill a hole in the BB shell, then get 30" of rebar, slip it through the BB up inside the seat tube to the seatpost, and pound it with a mallet. Sounds like fun !

EDIT...Seat post is Out ! See post # 41
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Old 02-23-20, 12:40 PM
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What 'cha working on?
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Old 02-23-20, 01:01 PM
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time for a video of the project
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Old 02-23-20, 02:10 PM
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Can't you just dissolve the seatpost with lye? Maybe less chance of damage to the frame.

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Old 02-23-20, 02:16 PM
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If it's a forged seatpost, don't forget RJ's options:



-Kurt
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Old 02-23-20, 03:45 PM
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I'd go the sodium Hydroxide route. Slow and steady not the strong violent stuff.
1 - Saw the post off close to the frame
2 - Invert frame in a bath of Sodium hydroxide (Lye) with 1" of post submerged
3 - Visit a pool shop and buy a steel or brass rubber pipe bung to fit seat tube.
4 - When the 1" has dissolved, block seat tube with bung.
5 - Work out roughly how much liquid you need to cover the rest of the seat post left inside the frame
6 - Fill from the BB or bottle cage boss.

In the dissolving stages you can listen for the bubbles. Fewer bubbles, time to change the solution. With 30% lye it should take about 10 days. You can even protect the paint to a large degree with rubber solution or neoprene glue.
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Old 02-23-20, 07:09 PM
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Originally Posted by cb400bill View Post
What 'cha working on?
A frame I built a Loooong time ago, and forgot about.
It's a bit too big anyway, so may go back into the spiderwebs in the basement.
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Old 02-23-20, 07:20 PM
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I like that seatpost puller !
Originally Posted by cudak888 View Post
If it's a forged seatpost, don't forget RJ's options:

https://www.youtube.com/watch?v=P-YpmDx86d0

https://www.youtube.com/watch?v=_gAXL2FSY_A

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Old 02-23-20, 07:45 PM
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Ive had good luck with this method.

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Old 02-23-20, 09:40 PM
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gugie would just replace the seat tube.
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Old 02-24-20, 07:51 AM
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Using a piece of rebar is guaranteed to put dents in the seat tube.
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Old 02-24-20, 07:55 AM
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Originally Posted by Moe Zhoost View Post
Using a piece of rebar is guaranteed to put dents in the seat tube.
The rebar shouldn't touch the seat tube. The idea is it slides through a hole in the bb shell, then inside the seat post.
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Old 02-24-20, 08:01 AM
  #13  
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One man's solution.
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Old 02-24-20, 08:29 AM
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My thoughts on these methods...

Using a chemical reaction: messy and difficult to control, this would be my last option.

Using a puller to extract the seat post straight out: very aggressive, if not straight out it could damage the frame; the video linked could damage the BB; puts a lot of pressure on the tube and risks something exploding

Drilling a hole through the BB and bashing some rebar up through it: my second-to-last option, as this is incredibly invasive (most especially to the bottom bracket!) and is a high risk of damage to the frame, especially if the seat post gets "kinked" in any way on removal.

Drilling the seat post and bolting a socket to it, then using an impact driver to rotate the seat post out: my first option, only damages the seat post, you can stop at any time, and is the fastest.

Clamping the seat post and using the frame (or some other long handle attachment to the clamp) as a lever to rotate it out: same concept as the impact driver, so would be another good option, though there is some risk to the frame. Being able to stop the process before any damage is done is a bonus.
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Old 02-24-20, 08:38 AM
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Originally Posted by Homebrew01 View Post
The rebar shouldn't touch the seat tube. The idea is it slides through a hole in the bb shell, then inside the seat post.
Ok, I get it now. I was thinking that you were going to tap on the bottom of the seat post rather than running the rebar to the top.
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Old 02-24-20, 08:42 AM
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The last couple of stuck posts removed I sawzalled the top off cut lengthwise, crafted a threaded rod into a slide hammer of sort.
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Old 02-24-20, 09:37 AM
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Originally Posted by ridelikeaturtle View Post
My thoughts on these methods...
Clamping the seat post and using the frame (or some other long handle attachment to the clamp) as a lever to rotate it out: same concept as the impact driver, so would be another good option, though there is some risk to the frame. Being able to stop the process before any damage is done is a bonus.
This seems like the first option that should be used. Probably not a whole lot of space to dissolve anything with PB Blaster or the like.
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Old 02-24-20, 09:46 AM
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I used the impact wrench method on my last one. It worked but not as easy as it did for RJ. The hard part was drilling the socket. I used carbide bits and a drill press but my press doesn't really run slow enough and it took a couple of bits per hole. I also cut one out but it was really corroded and I doubt the impact would have got it.

RJ the bike guy stuck seat post removal tools.

Always grease your post!
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Old 02-24-20, 10:20 AM
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Freeze the post as cold as possible, as the aluminum will shrink twice as much as the steel. Consider using dry ice. Maybe after freezing it for hours put a wet boiling water washcloth on the steel around the post, to maximize the size difference just before hammering. The corrosion is very strong but also very brittle so you want to have lots of sharp blows, a large slide hammer works well (when it does).
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Old 02-24-20, 11:54 AM
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Originally Posted by joeswamp View Post
Freeze the post as cold as possible, as the aluminum will shrink twice as much as the steel. Consider using dry ice. Maybe after freezing it for hours put a wet boiling water washcloth on the steel around the post, to maximize the size difference just before hammering. The corrosion is very strong but also very brittle so you want to have lots of sharp blows, a large slide hammer works well (when it does).
That was going to be my next attempt and I would have done it the first time along with the impact except the closest dry ice is 50 miles away. I have a tank of CO 2 that I froze things with but I don't know where to get it refilled any more. The DR Pepper guy had refilled it for me but that was 20 years ago.
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Old 02-24-20, 12:43 PM
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Originally Posted by TXsailor View Post
That was going to be my next attempt and I would have done it the first time along with the impact except the closest dry ice is 50 miles away. I have a tank of CO 2 that I froze things with but I don't know where to get it refilled any more. The DR Pepper guy had refilled it for me but that was 20 years ago.
Do you have any home brew suppliers around?
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Old 02-24-20, 01:04 PM
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Originally Posted by SurferRosa View Post
gugie would just replace the seat tube.
I have done that, it's not exactly a slam dunk. Dave Moulton says the seat lug is the hardest part of a frame to repair, and I now appreciate that. Now I want to replace the chainstays, so the whole enterprise seems a bit silly. I have some spare chainstays and I think I can reuse the seat stays, so it will probably work out.

I like the modified socket and impact wrench method, I might try that next time the opportunity presents itself. I tried using a pneumatic impact hammer which someone recommended. Didn't do anything, unfortunately.

I know someone that used to do removals for everyone in town. He would either pull them out with a winch or cut them out on his lathe. Had a bad experience on an expensive Ti frame and stopped doing it. I tried his lathe technique, but it turns out it's best if you use a smaller drill bit than I did. The chips from the seatpost destroyed the tube. Oops. I have thought of chucking up a boring head in my lathe and cutting them out that way. I think it would work.

Last edited by unterhausen; 02-25-20 at 08:08 AM.
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Old 02-24-20, 03:12 PM
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The only method guaranteed not to damage the frame is chemical, and although it takes a couple of weeks, the time involved is minimal. I did 2 posts and a BB last year like that and I don't think I'll ever go the violence direction on a stuck post again.
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Old 02-24-20, 03:14 PM
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I've had good luck getting a stuck seatpost loosened by attaching a sacrificial saddle to the seatpost then strapping the saddle t o a picnic table and then using the frame as a lever to twist the seatpost until it loosened.

Cheers
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Old 02-24-20, 03:30 PM
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Originally Posted by TXsailor View Post
That was going to be my next attempt and I would have done it the first time along with the impact except the closest dry ice is 50 miles away. I have a tank of CO 2 that I froze things with but I don't know where to get it refilled any more. The DR Pepper guy had refilled it for me but that was 20 years ago.
You can often get dry ice or CO2 at welding supply houses.
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