Stuck Seatpost After "Only" 30 years.
02-23-20, 12:32 PM
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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
EDIT...Seat post is Out ! See post # 41
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Last edited by Homebrew01; 03-01-20 at 02:03 PM.
02-23-20, 12:40 PM
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02-23-20, 01:01 PM
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time for a video of the project
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.
Last edited by smontanaro; 02-23-20 at 03:32 PM.
02-23-20, 02:16 PM
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If it's a forged seatpost, don't forget RJ's options:
-Kurt
-Kurt
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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.
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.
02-23-20, 07:09 PM
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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.
It's a bit too big anyway, so may go back into the spiderwebs in the basement.
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02-23-20, 07:20 PM
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I like that seatpost puller !
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
-Kurt
https://www.youtube.com/watch?v=P-YpmDx86d0
https://www.youtube.com/watch?v=_gAXL2FSY_A
-Kurt
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02-23-20, 07:45 PM
#9
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I’ve had good luck with this method.
02-23-20, 09:40 PM
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gugie would just replace the seat tube.
02-24-20, 07:55 AM
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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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02-24-20, 08:01 AM
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One man's solution.
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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.
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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02-24-20, 09:37 AM
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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.
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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02-24-20, 09:46 AM
#18
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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!
RJ the bike guy stuck seat post removal tools.
Always grease your post!
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).
02-24-20, 11:54 AM
#20
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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).
02-24-20, 12:43 PM
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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.
02-24-20, 01:04 PM
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gugie would just replace the seat tube.
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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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.
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
Cheers
02-24-20, 03:30 PM
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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.