Banging them out? Sealed bearing rescue....

2manyoranges

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So....the Grom messed about on the jump bike and said '...well there's something odd somewhere....'. He's perceptive for a 14 year old, and when there's something 'off' on any bike somewhere he's usually right. I took it out for a couple of circuits and yep, there was something in the transmission that I couldn't put a finger on...

After an hour of checking this and that and then that again, all I had left was the BB, so I pulled the cranks and put in a replacement from the workshop. Problem solved. And I had some new Enduro bearings so I was just going to do the usual 'whack them out and whack them back in' (using the right Hope tools, of course). But I stopped this time. The bearings had no play at all, they just were spinning fine, but then suddenly catching for no apparent reason. Horrible. And obviously a simple problem. Somewhere in there was some grit. So I did what we are 'supposed' not to do. I got a fine pick and pulled the bearing seals - the seals in the bearings themselves, not the Hope BB external seals. How the hell could grit get past the external seals, and then past the tightly-fitting bearing seals. No idea, but it had. The bearings were still in situ, so I blasted them with GT85. Still gritty. I blasted them with Mic-off. Still gritty. I blew them with compressed air. Still gritty. This was not going to work, having access to only one side of the bearing. So....nothing for it but to remove them, which means pressing on the inner race. A bad idea - pits the bearing surface. Oh well, nothing for it. Whack. One bang on the proper support, and out they came.

Pick took other seal off, now I have access to both sides. Finally, after much trial, this emerged as the best approach.

If bearing are dry, then grit falls out.

So....GT85 to denature the grease.
Muc Off to really clean everything.
Then run under vigrously-running hot water.
Water? Yep - dry instantly with air and place in sun or use hot air gun.
Then spin and spin, and out drops the grit.
10-minute job in the end, with the right technique.

Repack with Finish Line grease - not too much - don't overpack - click seals back in place.
Brilliant smooth bearings. Tight.
They won't be perfect, but I think they have long service left in them.

The important thing here I think is saving the planet - recuperating things not discarding them.
 
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