ryansu

So I am tearing down a 1992 Specialized Allez Sport and I am down to Frame and BB. The bb is a sealed unit and it seems to spin fine no notchiness or crunchy feeling and it occurred to me to just leave it be, however the bike is bone stock so I assume this is the original BB and thus 27 years old. Can I service it? Should I? Or should I leave it, or just replace it with a new Sealed unit?

I am used to working on cup and cone loose bearing BBs and not sure I have refurbed a bike that came with a sealed unit bb.

Thoughts?



the unit in question

tyrion

RJ did it:

fietsbob

Looks like the common Shimano UN type cartridge BB. Question is what is your time worth ?,
since the UN 26 is under$15.








....

ryansu

Yeah I saw RJs video and I don't have a vice or socket that big so I am leaning towards replacing. To bad there is no odometer on the bb to tell me how many miles it has I will probably spend an extra $5 and get a UN55 with the metal cups even though I am selling this I just prefer the metal cups

fietsbob

make sure you grease the threads on that metal sleeve on the left side..


the plastic one will not corrode..

dweenk

Call me lazy, but if the BB spins fine - I would wait until it doesn't. Fix what needs fixing.

madpogue 

Grease both. I've had at least one case of the plastic one seized in the shell, to the point where it cracked when I leaned hard enough on the socket.

If it's still smooth, I'd leave it. I've encountered a few that are rough and dry, and just managed to shoot new grease into them after prying off the seals with a little grease shooter like RJ's. Gets you another season's use, anyway.

Ryan, man you need to get a viSe. Indispensable tool. And if you've worked on a modern spark-ignition motor vehicle, the spark plug socket is 13/16", same as what RJ uses in the video.

Anyone heard how RJ is doing, BTW?

ryansu

Amen on the vice, I actually have one but its at the old house that my ex and my daughter live in and in an Apt there is no room for one but some day I will have one again. I think RJ has posted and I think he is doing better but taking it slow

ryansu

If I was keeping the bike I would definitely just use the stock BB which seems fine but since I am selling it when its done, just too small, I have ordered a new UN55 bb for the refurb and the stock one will go into the parts bin. Thanks everyone for the input.

madpogue 

You need a vise, not a vice. You probably already have a vice, like me -- if you consider wrenching on too many bikes a "vice"...

BTW, looking at RJ's video again, all he's doing with the vise is holding the spindle so he can loosen that locknut. You could probably do the same with an adjustable wrench on the flats of the spindle, and then turn a socket or box wrench on the locknut.

Oh, now I'm having a guilt trip. I'm prepping an '01 Hard Rock for sale, and the cartridge BB was pretty rough. I got it "pretty good" by the method I described above. But now you're making me think I should swap in a fresh one and relegate the original to the parts bin.

JohnDThompson 

I've rebuilt Phil Wood cartridges. I don't think the Shimano UN series, YST, Tange, etc. cartridges are worth the bother; it's cheap enough to just replace them when they die.

madpogue 

Update - I was able to take one apart by putting a 15mm 12-point box wrench on the taper flats, and a 13/16 6-point spark plug socket (I cracked my regular 13/16 6-point Craftsman) on the locknut. BB is definitely improved with fresh grease. But given the time and frustration working with 12 balls on one side and 18 on the other, I would tend to agree with John. Interesting exercise, but not something I'd do unless in a pinch.