Best way to clean a square taper bottom bracket

Goudgey

Goudgey

Likes Dirt
Hi all,
Whats the best way to clean and re-lube a square taper bottom bracket?
I want to make sure I don't do anything that will stuff it up.
I'm thinking that I should hit it with degreaser then apply a liberal amount of grease/lube before refitting into the frame.
Is the degreaser a bad idea?
Cheers
Mark
 
guitar1234

guitar1234

Likes Dirt
degreaser will likely remove the grease from the bearings, also don't grease the ends of the bottom bracket where the cranks go onto, they will slip and kill your cranks :nono:
 
The Duckmeister

The Duckmeister

Has a juicy midrange
If it's a sealed cartridge unit, there's not much you can do to the guts of it... If it's running smoothly, great. Clean any crap off that you can get to, and clean out the frame as well. Grease the frame threads (tip: greasing these means that as you screw the BB in, the grease will be pushed in ahead of the BB. If you grease the BB threads, the grease will be pushed out and not get to where it's needed) and inside of the left guide cup. Screw the left cup in about 2/3 of the way, then screw the main body of the BB in, snugging it up tight. Then tighten the left cup. If it's running rough (you'll either feel it, or if you hold it near your ear & spin the axle it'll sound like it's full of crap), chuck it & buy a new one. It'll only cost about $20. Then install as above.

Contrary to the post above, my belief is that you should grease the spindle ends. Ungreased, the alloy crank arms will cold-weld themselves onto the chro-mo spindle, and when you do want to pull them off, you're more likely to pull the thread out of the crank arms, winding up with really stuck cranks. Ensuring the crank bolts are very well tightened, and checking after you've done a couple of rides will ensure the cranks stay where they're meant to.
 
D

Deleted member FN2187

Guest
Step 1: remove from frame.
Step 2: lift bin lid and dispose of.
Step 3: purchase external BB and cranks, install.
Step 4: put feet up.
Step 5: crack beer.
Step 6: smile and pray good riddance to bad technology.
 
Goudgey

Goudgey

Likes Dirt
Thanks for the advice guys. Will do as you suggest Duckmeister.
Not a lot of love out there for the old square taper BB it would seem!
 
D

Deleted member FN2187

Guest
Sorry, just being a smart arse. If it works for you no need to upgrade. But really if the bearings are shot, a new BB is needed.
 
flamin'trek

flamin'trek

Likes Bikes and Dirt
Square taper BBs are fine, just heavier than current external setups. If your BB is not a sealed unit (ie off and old bike/cheap bike) just pull it completely apart, watching where stuff comes from, give it a good scrub and clean then regrease and put it back together. I have pulled a few of these old cup and cone adjustable BBs recently with old road bikes and kids bikes and inside they were surprisingly good condition. a quare taper unit can be had for as little as $10 online too.

+1 for a little lubricant on the taper before cranks go on, but only a very light smear.
 
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