Bicycle Mechanics - Creaky sealed-cartridge bb?

I've got a creak in the bottom bracket of my "rain bike" - which is a Shimano sealed-cartridge type. I pulled the BB out last night to re-lube the cranks and BB threads, and there's oil / lube in the bottom bracket shell... not grease, but a lighter machine oil of some kind. Is the BB likely to be leaking lubricant? I can't see any crackign or anything... Is this a user-servicable part, or should I just plan to replace the whole BB assembly? It still spins smoothly, but the creak seems to be worsening...

Thanks!

-chris

I've got a creak in the bottom bracket of my "rain bike" - which is a Shimano sealed-cartridge type. I pulled the BB out last night to re-lube the cranks and BB threads, and there's oil / lube in the bottom bracket shell... not grease, but a lighter machine oil of some kind. Is the BB likely to be leaking lubricant? I can't see any crackign or anything... Is this a user-servicable part, or should I just plan to replace the whole BB assembly? It still spins smoothly, but the creak seems to be worsening...

Thanks!

-chris

I'm thinking that you're going to need a new bottom bracket before long. The cost of the part is the same however you do it, but it's quite a bit more convenient to change it out while you have the bike in the shop than it is if you wait until it fails on the road.

Cartridge BBs are not really serviceable. If it is a square taper spindle, you should be able to find a replacement for about $20-25 at any LBS.

I've got a creak in the bottom bracket of my "rain bike" - which is a Shimano sealed-cartridge type. I pulled the BB out last night to re-lube the cranks and BB threads, and there's oil / lube in the bottom bracket shell... not grease, but a lighter machine oil of some kind. Is the BB likely to be leaking lubricant? I can't see any crackign or anything... Is this a user-servicable part, or should I just plan to replace the whole BB assembly? It still spins smoothly, but the creak seems to be worsening...

Thanks!

-chris

The light oil could be the remains from when the shell was machined. Off hand, I wouldn't think its from the BB, since there is no direct path from the BB to the shell, from the point of view of where the oil is.

Its not user servicable. You just chuck em when they go bad. New ones cost $20-$40, assuming a typical UN-XX with tapered spindles. Others will cost a bit more.

According to the Barnett manual (http://www.bikeforums.net/barnettes/barnetts_ch10.pdf , second page) creaking in the BB is lack of torque on the adapter ring, looseness between adaptor and cartridge or fix ring working loose.

Thanks, all! I'll try the loctite trick described in the Barnett's manual, but it sounds like I'd better start keeping my eyes open for a deal on a new BB. I don't think the oil is from machining - it's quite a lot of oil, not just a light coating... enough to seep through the BB threads and drip off the bottom bracket shell. But you're right - I can't see how oil would be getting to where it is inside the shell from inside the BB assembly iteself. My current thinking is that perhaps it ran down a body tube from something else that the previous owner lubed with light oil - seatpost or stem.

Thanks again!

-chris

Thanks, all! I'll try the loctite trick described in the Barnett's manual, but it sounds like I'd better start keeping my eyes open for a deal on a new BB. I don't think the oil is from machining - it's quite a lot of oil, not just a light coating... enough to seep through the BB threads and drip off the bottom bracket shell. But you're right - I can't see how oil would be getting to where it is inside the shell from inside the BB assembly iteself. My current thinking is that perhaps it ran down a body tube from something else that the previous owner lubed with light oil - seatpost or stem.

Thanks again!

-chris

Just an FYI. The one time I had my BB changed by the LBS it was $35, parts and labor. That was a UN53 series bracket.

Since then, I've bought the tool and have done others myself. Sounds like you already have the tool. Nashbar has em for a fairly good price, they also have a generic, though I haven't tried em.