Support Team Shaun_E Posted May 31, 2009 Support Team Share Posted May 31, 2009 I have a steel framed mountain bike in which the aluminium seatpost has seized. I have tried penetrating fluid and hitting it hard with a mallet but it just won't budge. Has anyone got any suggestions on how to get it out? I would sacrifice the seat post if the frame could be saved. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 31, 2009 Share Posted May 31, 2009 Have you tried PlusGas ... soak it each day for a few days. Maybe grip the seatpost with something like Footprints and try and turn it. If it moves, keep turning and try to 'unscrew' it out of the frame ? Link to comment Share on other sites More sharing options...
Myles Posted May 31, 2009 Share Posted May 31, 2009 Oh god! An absolute nightmare! I don't have a solution, but I have had two recent experiences trying to remove seatposts from corroded ali frames. One was a carbon-wrapped post - the wrapping gave up in the tube and I think there was some ali/ali corrosion. That one needed a couple of people and a vice - and the seatpost lost but the frame was saved. I've another frame with a full-carbon post in it. The ali has corroded again - and the post doesn't want to come out. I want to save both, but have put this job aside for now. I'd hate to have to tackle a steel/ali job Leverage, plusgas and/or heat - I guess those are your options. I don't think whacking it will really help. 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester Racing 7s Ecosse™ 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Jorgen Posted May 31, 2009 Share Posted May 31, 2009 If the frame is worth a respray it can be heated out. The seat post will melt out of the frame which will still be ok. But obviously it will need a new coat of paint. You can do it your self but its better to have frame builder do it as you can ruin the frame with excess heat. jorgen Link to comment Share on other sites More sharing options...
Beelzebub Posted May 31, 2009 Share Posted May 31, 2009 I've been here before with Mrs Davesport's winter training bike. Whatever you do don't apply a lot of pressure to either the seatpost or the frame. It's very easy to damage the tubing. Accepting that the seatpost is now part of the frame is the most difficult part. They're effectively welded together by expansive corrosion by-products. Irrespective of how tightly the seat post is seized into the frame, the major complication is the amount of seat post that's inside the seat tube. What I started off by doing was to hacksaw the remnants of the post off about 20mm above the top of the seat tube. Flush the end of the post off with a file & then measure how far the post penetrates into the frame. The seat post I was trying to extract did'nt have the internal bore to accept a hacksaw blade. So I had to use progressively larger drills to carefully increase the size of the hole to the full depth of hte post. I did this until I ran out of suitable drills & this left me with a shell of about 3 or 4mm to split using a hacksaw blade. Take it easy near the end as it's easy to mark the inside of the seat tube. You can tell when you're getting close as the hacksaw cut begins to close as the shell collapses away from the frame. After a good lashing of Plusgas the remnants can be withdrawn using molegrips. The final step is to open the fridge & have a couple of wets 😬 D Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 31, 2009 Share Posted May 31, 2009 Shaun, Spin the bike upside down less the wheels, clamp the seat post in the vice (assuming the post is to be sacrificed) then spin the frame around it, I've Shifted loads in this manner. If the clamp comes away in the vice which it can, firstly give the end of the post a few firm sharp blows with a knocking stick then drill a 10mm hole straight through the post to allow you to put a bar through to prenvent it spiinning when clamped in the vice as above. Naturally if you can soak with plus gas for 24 hours this does help. Good luck. Too young to be old ! Edited by - 7 wonders of the world on 31 May 2009 20:49:21 Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted June 1, 2009 Author Support Team Share Posted June 1, 2009 Thanks for the suggestions. I'll give them a try. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted June 1, 2009 Share Posted June 1, 2009 Got in this situation when I used a seatpost that was 0.2mm too large... Well, it looked the same And bizarrely, went in fine... Anyway, easily removed by taking off the wheels and saddle, clamping the seatpost in a vice, and turning the frame, a la 7WOTW. Get a seatpost from DMR or similar, I've had mine nearly 7 years, and still zero corrosion between post and frame. J'adore le steel. John _________________________ Bugsy: '82 2cv6 (Back on the road!!! 😬) Talloulah: '08 1.6K Classic (Grubby ) Link to comment Share on other sites More sharing options...
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