jhc

I picked up an old Specialized Crossroads to rebuild for a friend. I went to remove the bottom bracket, and it is stuck. At first I thought it was a standard sealed bb, but on closer inspection, I realized it was... different:

The left (non-drive) side is threaded and has what appears to be a nut on the spindle itself (the first & second pics). The drive side, which I tried to loosen, is plastic and broke away (third pic).

Any idea what this is, and more importantly, how do I remove it? I've been searching the forums all day, but I don't even know how to describe this in a query.

thanks for your help.

Torchy McFlux

It's a Shimano cartridge BB. Extremely common. That nut on the spindle doesn't need to be touched.
You should have removed the left side first. Then spun the right side out - the driveside thread is reverse, so you should turn it clockwise.
Are you using a proper splined BB tool?

jhc

thanks. I've just never seen a threaded spindle like that, I tried to remove the left side first, but it's frozen. I hit the right side just to see if I could loosen it and it cracked. I'm using the park BB tool, but it's a bit loose, so I'm trying not to strip out the splines. Any tricks on getting more torque on the BB tool?

LarDasse74

If you are using the park tool with a wrench (instead of with the 3/8" ratchet drive) then you can actually fasten the tool to the bottom bracket spindle with a long bolt, thus holding the tool in place while you apply torque. You can then put a cheater bar on the wrench, or even put the tool in a solidly mounted bench vise and turn the bike to loosen the cup.. You must be sure to loosen the bolt a bit once the bb starts moving.

Beware that sometimes the cups are really stuck in there and it takes more torque to remove them than the little teeth on the cups can provide. I find a little rubbing alcohol soaked into the threads can help - but thre are many many other proven techniques for freeing seized bb cups.

Good luck!

jhc

thanks. I'll have to find a longer bolt that fits the crank bolt threads, but that's a great idea. And since I've already exposed my ignorance, I'll ask: Isn't the plastic cup usually on the non-drive side?

LarDasse74

Depends on the model of bottom bracket. It sort of makes more sense, yeah, as traditionally bottom brackets had a 'fixed' cup that was just tightened like crazy against the frame on the drive side, and an 'adjustable' cup that was positioned based on bearing fit on the non-drive. But some cartridge bottom brackets I have seen have the plastic cup on the drive side and the metal 'fixed' cup on the non drive. I can't imagine why they would make them like that.

JustChuck

The spindle is threaded because that is an adjustable cartridge BB. You use a pair of wrenches(Park makes them) that are made to nest inside one another to loosen the stop nut and adjust the cone. There is a rubber seal you might have to pull out to see the nut/cone clearly.

Mondoman

If you haven't already, squirt some penetrating oil (like PB Blaster) around the outside of the BB on the NDS, right where the BB shell face meets the BB. If you can get the rest of the plastic out, you can squirt PB Blaster into the shell area from that side, too.