Removing crank and BB

[brentville]

I have an older mountain bike with what I guess is a sealed bottom bracket. The crank arms bolt to the square axle that goes through the bb. I got the bolts off but not the crank arms. Any tricks to this? Do they just need to be broke lose and pounded off with a hammer?
Is there a more sophisticated way to do this?
And how does that bb come out?
Thanks

 

[OG1]

I have an older mountain bike with what I guess is a sealed bottom bracket. The crank arms bolt to the square axle that goes through the bb. I got the bolts off but not the crank arms. Any tricks to this? Do they just need to be broke lose and pounded off with a hammer?
Is there a more sophisticated way to do this?
And how does that bb come out?
Thanks

yes, there is a tool for it. called a crank arm puller. any other method will probably destroy your crank arms.

 

[Sinner4]

For 15 bones you can get a BB Remover. No no need to bash with a hammer. Park tools make em. Got mine at a bike shop. Broke it the first time on a stuck crank. Park sent the new part out the next day. Been fine and have used it on 20 BB's and still working.

 

[brentville]

Thanks for the advice. Good to know this before I got out the hammer. I just wanted to open up the bb to lube it and maybe change the crank set. Now I'm wondering if those sealed bb's even need to be lubed or can really dry out at all?

For a few bucks spent on the park tool I could find out I guess.

 

[deorman]

They may or may not be sealed, a lot of MTB's have regular ball bearings, especially older ones. Once you have a crank arm puller, it will be easy enough to open it up and find out. Loosen the lock ring, then the retainer should easily unscrew. If a sealed bearing feels like it needs cleaning or adjusting, it's time to change it. http://sheldonbrown.com/gloss_bo-z.html#bottom