I have an aluminum bicycle seat tube stuck in a steel frame. I have been using penetrating oils and heat and hammering and such to loosen the corrosion. Now I drilled a hole in the seat post, and can insert a metal rod.

How do I grip the rod with good leverage to turn out the seat post? Thanks for any advice. I don't have a socket extension, so I'm showing the image below with a screwdriver. I have an adjustable end wrench (25cm), but nothing bigger. I could rent something if necessary. So far, I can't turn it. Thanks for any advice!

seat post


  • 3
    I’m voting to close this question because it has nothing to do with Home Improvement. Sep 5, 2020 at 11:07
  • I'm new here. Is there another community that would be a better fit? Sep 5, 2020 at 11:08
  • 3
    How about bicycles.stackexchange.com? Sep 5, 2020 at 11:47
  • yes, makes sense. I find the tags in this community a closer fit to this specific question—how to accomplish leverage on a corroded metal connection—but I agree it is a bicycle part being leveraged. Sep 5, 2020 at 11:54
  • Have you tried hitting the screwdriver with a hammer on each side of the pipe in the direction of the seat?
    – JACK
    Sep 5, 2020 at 12:09

2 Answers 2


This, unfortunately, is a common and difficult problem. The issue is corrosion between the Aluminum and Steel and it can make it difficult and sometimes impossible to separate them.

Here is an article from Sheldon Brown that describes some causes, prevention, and fixes:

Sheldon Brown Seatpost Article

I suggestion trying #9 to start with.

  • Good resource: I did read that and several other long threads on the topic. I haven't tried ammonia yet. Sep 5, 2020 at 10:50
  • Keep in mind, however, that in some cases the two parts cannot be separated without ruining the bicycle's seat tube. Good luck!
    – jwh20
    Sep 5, 2020 at 11:04
  • Agreed, and that's fine in this case. Hoping not to damage the frame, but that's possible also. This particular seat tube ends in a suspension mechanism, and previous liquids I've poured in the frame came out that mechanism (slowly). So now I'm wondering how I might block the inside of the seat tube so the ammonia doesn't flow through. Maybe a balloon? Sep 5, 2020 at 11:07
  • I blocked the inside of the seat tube so the ammonia doesn't flow through with an inflated latex glove. Sep 5, 2020 at 11:53
  • 1
    @CameronBrick slow down - approach this methodically or you'll risk ruining the bottom bracket and bearings too. Try chat.stackexchange.com/rooms/214/the-velodrome where this is on-topic.
    – Criggie
    Sep 11, 2020 at 5:05

I use my drill press. Restore a lot of 80s bmx where they used aluminum race seat posts and some chromoly ones I’ve had stick. Steel on steel patience and time is a virtue.

Now aluminum fuses during the elements in the air and it can basically weld itself to the steel in a sense. Depending on size of post it can get tricky. I’ve always had to do 7/8!mosts so easy bit to find. Now a say 27.2mm post I have used 1 1/8 but and a long chisel to hjammer out the remaining aluminum. It’s not fun but black totally be done and never mess up the frame.

  • 1
    Explaining how you use the drill press would sure help your answer.
    – JACK
    Jul 26 at 23:58
  • Editing to fix all the typos would go a long way toward making this understandable, too. Honestly, what does "It’s not fun but black totally be done and never mess up the frame." mean?
    – FreeMan
    Jul 27 at 13:10

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