Removing damaged BB cups from MTB frame.

Run_to_da_hills

My younger brother snapped BB axle in a top end alloy MTB frame and needs to remove cups to replace it however cups are seised solid so much that the splines have become damaged making them impossible to remove with the correct tool. Is there any recommended tips or any bike shop recommended? Bike is currently stripped down.

Cheers.

billy.fish

If its an external BB and you dont want it anymore - vicegrips. TURN THE CORRECT DIRECTION.

If you aint confortable, bring it to your LBS.

Run_to_da_hills

billy.fish wrote: »

If its an external BB and you dont want it anymore - vicegrips. TURN THE CORRECT DIRECTION.

If you aint confortable, bring it to your LBS.

Its internal BB and I am familiar with L & R H thread direction, local bike shop couldn't do much.

billy.fish

Run_to_da_hills wrote: »

Its internal BB and I am familiar with L & R H thread direction, local bike shop couldn't do much.

Have you got a vice and bench??

seamus

Can you post a pic of the type of BB from the web?
If it's one of these, it's going to be very difficult;
http://upload.wikimedia.org/wikipedia/commons/0/09/BB-UN73.jpg
Not impossible though - cheaper units have a plastic cup on one side which can be broken.

Have the splines on both sides been stripped?

Run_to_da_hills

seamus wrote: »

Can you post a pic of the type of BB from the web?
If it's one of these, it's going to be very difficult;
http://upload.wikimedia.org/wikipedia/commons/0/09/BB-UN73.jpg
Not impossible though - cheaper units have a plastic cup on one side which can be broken.

Have the splines on both sides been stripped?

Yes unfortunately that type and both cups are metal. I tried heating the base of frame with no joy. Looks like a bar might have to be welded on to the cups.

seamus

Run_to_da_hills wrote: »

Yes unfortunately that type and both cups are metal. I tried heating the base of frame with no joy. Looks like a bar might have to be welded on to the cups.

If you have that kind of expertise available to you, then it may be the best course of action.

When these BBs seize, they can be a pain in the ass, I've had to stand on a huge spanner and bounce up and down to release one before.

Run_to_da_hills

seamus wrote: »

If you have that kind of expertise available to you, then it may be the best course of action.

When these BBs seize, they can be a pain in the ass, I've had to stand on a huge spanner and bounce up and down to release one before.

Frame is AL 7005, I would be afraid to swing off it too hard.

paddyduc

If you can run a bolt through your BB tool and into the axle it will stop it slipping on you. Turn the right side one clockwise and the left one anti-clockwise.

Run_to_da_hills

paddyduc wrote: »

If you can run a bolt through your BB tool and into the axle it will stop it slipping on you. Turn the right side one clockwise and the left one anti-clockwise.

There is a broken solid axle in the BB.

paddyduc

Your best option now is to weld the axle to the cup and put and old crank on it to turn it.

Run_to_da_hills

paddyduc wrote: »

Your best option now is to weld the axle to the cup and put and old crank on it to turn it.

Thinking of similar.

paddyduc

I've done this a few times, works a treat. As the weld cools it will shrink the cup leaving it easy to open.

Run_to_da_hills

paddyduc wrote: »

I've done this a few times, works a treat. As the weld cools it will shrink the cup leaving it easy to open.

Cheers

Run_to_da_hills

paddyduc wrote: »

I've done this a few times, works a treat. As the weld cools it will shrink the cup leaving it easy to open.

Got them out today, welded cups to axle and twisted frame in vice. Once I got the first one out the second came out very easy. Cheers again.

paddyduc

you're welcome, glad it worked out for you.


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