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Diff fluid in drum brake

jimbc

Member
Hello

I have an 85 R80 and diff fluid is getting into the drum brake. It's getting in from the pressed in sleeve where the shaft that spreads the shoes goes through the diff. I've cleaned and sealed the end of the sleeve with RTV a couple of times but it always starts leaking again and of course soaks the shoes with diff fluid.

The diagram doesn't show the diff, but p/n 21 is the shaft that goes through the sleeve that activates the shoes. I hope this helps to visualize what I'm refering to.

Any suggestions would be apreciated.

Thanks, Jim
 

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One option is cleaning the pressed in area very thoroughly with a degreaser (naptha, acetone, brake cleaner, etc) - letting the degreaser solvent evaporate - then applying loctite 290 on the seam at the interference fit. If done with care and deliberation there is a good chance the wicking action of the 290 will fill the gap then harden to stop the seeping. Anything more than seeping is beyond the usefulness of a product like loctite 290. Do not use 290 'liberally' as it can cause problems if misapplied. I recommend applying with a saturated q-tip then wait 24 hours before use. Good luck!
 
Thanks for your input Stan - as the bike is parked for the winter, I have lots of time - I will drain the diff, clean, let dry and try the loctite - Jim
 
I had this same problem last year on my '83 R80. Id be willing to bet that your leak is a result of worn out o-rings on the brake cam-shaft itself. I replaced the rings on mine and greased the shaft up with silicone grease. Been fine ever since. Easy and cheap fix. Well, excluding the price of new brake shoes. Check how many o-rings you have and order appropriately. I only say this because the parts fische for my bike said qty (2), but there was really (4).
 
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