The park tool site has good step by step instructions. Questions answered inline below:
My bottom bracket is clicking quite a bit. I understand that it may need re-greasing. I have a crank puller and a bottom bracket tool and I have done this before, but I am not sure if I did it right. Is there a good online description of how to do this (I have shimano style cranks and bb).
Clicking can be lots of different things. But rebuilding is a good first step, also check your bearing cages for tweaking if you have them.
- should you release the chain tension first?
ideally, yes, but if your chain tension is exerting substantial force on the BB just sitting there it's too tight, which may have caused your problem in the first place
- do you need to remove both cranks?
To adjust most BB's you don't need to remove either crank, but if you're going to pull one pull them both. I find I need both cranks off to feel if the BB is gritty and needs to be overhauled, I've had bikes where the cranks seemed to spin ok, but I could barely turn the spindle by hand once I had them off.
- do you need to clean the BB and completely re-grease it, or just wipe it and add a bit more grease?
If you're going to bother to tear it all the way down, clean that sucka out like you mean it, and give it new bearings as well as new grease. Bearings are very cheap.
- how much grease should there be?
Can't really overdo it, I mean you don't want to fill the whole BB shell but the cups should be essentially full.
- is it ok just to tighten up the cups, or should you really take the BB out and clean it etc?
If you think things are in good shape inside (recently regreased, no major riding in slop, etc...) just tightening up the adjustable cup is par for the course.
- is just tightening the allen bolt in the center of the cranks enough to get the cranks back on?
Yup, and it's not only enough, it's all you should use. Beat on them and they won't go on evenly. Also, if all you have is a multitool, unless you have wrists like a gorilla you probably aren't getting your cranks on tight enough, torque spec on this is about 30 lb-ft.
hope that helps