The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Miker on 17.02. 2020 12:31
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Hi, I have just installed a sealed bearing to the rear brake hub of my plunger A10. It seems that there is not enough space when I put in the Rear brake Hub Bearing seal cover (67-6072) for the Bearing circlip (67-6067) to go on. I have it all in but the circlip is not sitting properly in the groove. Since I have a sealed bearing is it ok to leave the seal cover out. Thanks for any help.
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The original bearing 89-3022 is an imperial size 1" x 2 1/4" x 5/8" You may have ended up with a modern metric equivalent, and the variation in width is just enough cause the problem. Make sure there is nothing to stop the new race seating in the drum. We also assume the drum is a genuine part, so a slight error in machining if a pattern part may also account for the misfit.
The seal cover could be omitted, as the shielded bearing will retain the lubricant. The only downside is the bearing will now have theoretical scope for a small amount of lateral movement. This would need to be eliminated by a custom circular shim between the circlip and outer race, to replace 67-6072.
Swarfy.
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I left the covers out when I rebuilt mine on good advice from several people.
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So what is this 'modern metric equivalent'?
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Imperial bearings were once in short supply as I understand and it is possible that suppliers offer a metric equivalent which would substitute for the correct item. Checking the width of any new bearing against the original would be a first step to solving the mystery.
Swarfy.
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Usually here is NO METRIC EQUIVALENT
Metric bearing will be either 12mm, 13 mm or 14 mm wide , none of which is exactly 1/2"
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89 3022 is bearing RLS8 and LJ1.
I usually source bearings from a bearing specialist not a bike dealer.
https://simplybearings.co.uk/shop/advanced_search_result.php?search_in_description=1&keywords=rls8