Tricky bearing repacking question

I have a tricky issue involving repacking a pair of bearings. My unique bicycle (GT I-drive for those keeping score) has a non-standard part called an eccentric, which is an aluminum tube about 9.2 cm in diameter and 6.8 in length, in which 2 bearings have been pressed. They are large circular, with the ball bearings between 2 "U"s and a very thin metal sealing strip on each side. Well, long story short, when the bike was manufactured, all sorts of aluminum machining debris wound up in the eccentric, and even some specks in the bearing assembly. Needless to say it is a little scratchy running. I have cleaned it once with good results, but I can still hear a couple of bits of debris on each one. I am going to go for broke and clean and repack it again to get it running as smooth as possible.

Due to the nature of the beast, it cannot (by me) be removed (I don't think - anyway I really don't want to damage the unit). The bearings appear to be pressed in, stopping against a metal bearing retaining ring (a kind of 15/16ths metal circle that clicks into a small groove).

So, in order to do this, I will remove the outer seal strips and take them away. The inner strips and o-ring locks will remain "trapped" between the 2 sets of bearings for this operation (while the unit is dry, I plan to tape them in place in the very middle to keep them out of the way). The question:

What is the best cleaning method to make sure I get all debris out?

I think I can mount the bike in a stand with the part in question over the sink, and so I am thinking of scrubbing with degreaser and a toothbrush in between blasts of warm soapy water (from the faucet). Then air dry (blowdryer) and repack. Obviously I am not a machinist, and really if you haven't figured it out yet don't know what I am doing, so hopefully some of the experts here can give me some help. Thanks in advance.

Reply to
ss
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I meant to say 6.8cm not inches in the last post.

Reply to
Shon Shampain

Reply to
Rex B

Solvent (not water!!!) and compressed air. Paint thinner (mineral spirits) is a good "wash" solvent.

Soak in solvent, blow that out with compressed air, follow with BrakeKleen which doesn't leave a residue, blow out again and repack.

If you don't have compressed air, take it to someone who does.

Reply to
Don Foreman

From what I've heard those I-Drive bottom brackets are put together a lot like regular cartrige-bearing headsets. If you know what that means, have at it--easy to pull/push/hammer apart in that case. OTOH, if you don't, it'll be worth a few bucks to go down to a bike shop and ask them to remove, clean, and repack the bearings. Just make sure it's a place not staffed by dopes. You could try posting to rec.bicycles.tech--they can tell you exactly how to get it apart with no damage, or the best way to clean it up without removing it. I know it won't involve water, though.

Reply to
B.B.

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