Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  

Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Thread Tools Search this Thread
Old 09-26-08, 10:50 PM   #1
Thread Starter
Ayyyyy's Avatar
Join Date: Jan 2008
Location: Eugene
Bikes: 1990 Serotta Noval Special X, 2009 Giant Bowery '72
Posts: 30
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Broken & Rusted cottered crank

I'm trying to remove the crankset and bottom bracket from an old Phillips frame I found, managed to get one of the cranks off, but the threaded end of the cotter on the other crank snapped off after trying to hammer it out. I've been pounding at it with a hammer & screwdriver, but it doesn't seem to want to move at all. Is there anything I can do, or somewhere I should take it?
Ayyyyy is offline   Reply With Quote
Old 09-27-08, 03:33 AM   #2
Senior Member
mike's Avatar
Join Date: Jul 2000
Location: Snowy midwest
Posts: 5,392
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
If you pound the crank enough, you will damage or break the bearing cups. Can we assume that you did not use a support block under the crank cotter before you pounded on it?

You are experiencing the intense feeling of "COTTERS SUCK!".

Back in the days of cottered cranks, the pro wrenches had cotter presses to remove and replace cotters. In today's world, there are some tricks you can use to get it out, but in my humble opinion, the crank might be hosed.

First, if you can get one of the pedals off and remove the stuck pedal and axle, do that first rather than banging on the crank while it is on the bike.

If the stuck cotter is on the left crank side and you can't remove the crank/axle from the bike, you can try this; Take a 2 X 4 and cut it so it will fit under the crank arm by the bottom bracket. Cut a "V" notch into it so the cotter pin head rests in the recess of the 'V" notch.

Put some naval jelly or oxolic acid around the rusted cotter as much as possible and let it soak overnight. Rinse, then spray with Liquid Wrench over night.

Then, it's Hammer Time. Use a punch and a hammer to knock out the cotter. A broken pedal axle makes the perfect punch tool. Don't even think of using a typical nail counter-sink punch. That won't work.

When you it the punch/cotter you have to do it with a really good sharp whack - don't ***** foot. A heavy hammer is better than a light one.

If you are lucky, she will break free.

Last edited by mike; 09-27-08 at 08:20 AM.
mike is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 01:24 AM.

  • Ask a Question
    get answers from real people!
Click to start entering your question.