How would you approach this? Bicycle bottom bracket.

[Perry]

I have a bottom bracket on a bicycle that is seized in placed.

The thread is a left-hand thread, which tightens counterclockwise and loosens clockwise. (Just thought I would mention this.)
I have the proper tool for the spline and it sheared the female interface and also damaged the tool slightly. I tried lots of WD40 and a punch and a BIG hammer. No joy.

The axle is hardened. Drilling it out is unlikely. I may be able to cut a good chunk of it off with a Dremel. Then try to grind the remaining stub untill I can remove it. Then I can work away at the bracket case with a hacksaw. The axle seems to have a hollow internal section that is a fair bit deeper then the thread that would hold the crank arm on. This may work to my advantage. The hollow section does not go 100% thru from one side to the other.



This image is for reference. The bracket case I'm working on appears to be something other then aluminum. (Steel?)

 

[RobinHood]

I would try with lots of heat. Oxy-fuel preferred, as a propane torch may not have enough heat output with the frame acting as a heat sink.

If the reference part is any indication, looks like there could be some sort of thread locker in there that you are fighting.

 

[Perry]

Thank you Robinhood. I thought about the heat. Scared I might ruin the frame. (Might save this for a last resort) I see a few of the new units come with a thread locking compound, some with grease.

I took the seat post off and filled it with WD40. Hopefully that will seep down and maybe work its way from the backside. Going to let it sit overnight and give it a shot tomorrow.

 

[Johnwa]

There might be enough of the female spline left to hold your wrench (I’m assuming it is a socket type) and then drive it with an impact wrench.

 

[Perry]

There might be enough of the female spline left to hold your wrench (I’m assuming it is a socket type) and then drive it with an impact wrench.

It does have a socket. I used a C clamp to keep the tool firmly seated. (This covered up the socket drive). Then used my large crescent wrench to drive it. It's really in there. That's what caused it to break. I'm not sure there is enough material left to try the impact drive. Even still, I don't think keeping it square and firmly mounted would be easy. When I realized it was tight, that is when I came up with the C clamp idea. I was sure it would slip and I would mess it up. Well it didn't slip.

Thank you for the ideas Johnwa.

 

[DavidR8]

I ran into that exact problem. The only way it came out was with heat. The previous ahem, 'mechanic' put it in with lots of red loctite as I could see it.

 

[Perry]

I ran into that exact problem. The only way it came out was with heat. The previous ahem, 'mechanic' put it in with lots of red loctite as I could see it.

Red...Blue...same thing. lol. I'm really hoping it's not the red.

Thank you for the input David.

 

[Crankit]

What's the frame composed of?

 

[DavidR8]

What's the frame composed of?

From the lack of weld fillet on the bottom bracket welds I'd say cro-mo steel and not aluminum.
But that's just an educated guess.

 

[YotaBota]

Can you weld a piece of pipe onto whats left of the female interface and use the pipe for leverage? Just the act of welding may break it loose.

 

[Dabbler]

The only time I encountered a problem as bad as this was on my old Zeus racing bike which had been outside for 15 years. I used abrasive techniques carefully and sectioned the Campy Nuvorecord bottom bracket out of the frame. I was lucky and found a superrecord bottom bracket that was cheap enough to replace it with.

You can use heat, but you'd be wise to buy temperature crayons, and make to maximum heat to the frame less than 300F. If it is a chrome-moly frame it begins annealing just above 300F. This will damage the paint, but shouldn't hurt the frame.

 

[Perry]

Success.

I'm not sure if it was the rest I gave my arm and hammer or the overnight soaking of the WD40. (from the inside) It still was not easy, but it is out. It appears corrosion was the issue.

The frame was a cro-mo steel. It's an older bike. Good bike. It has a low visual appeal. I like to use it when I don't want to leave my nice bike anywhere.

A can a of worms was opened when I decided to replace the rear cassette. Well that led to a new front set of sprockets and a new chain. Might as well replace the bottom bracket cassette since I was at that point. Should have bought a new bike. lol.


Thank you for all the ideas.

 

[YYCHM]

So show us what you removed and what you're replacing it with please. Bracket doesn't make sense to me

 

[Perry]

So show us what you removed and what you're replacing it with please. Bracket doesn't make sense to me

Craig, I hope this helps.
The piece going in is basically the same as the piece that came out. They call it bottom bracket. Also known as a cartridge. Sealed bearing unit.