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What to do about rear brake?

Posted: Thu Jun 12, 2014 2:32 pm
by George inMinneapolis
Last summer I had the rear seal go out on my R80/7. The brake shoes and drum were covered in oil. A BMW repair person fixed the seals and cleaned up the shoes and drum. After that, the rear brake worked pretty well, as well as usual for an airhead. When I'd apply the brake there would be a squeak but it would stop. I was told the squeak would go away after the shoes "bed in". After a while, I started noticing that there no longer was a squeak and the braking performance was not so good. Rear seal again? I took off the back wheel, and no oil. I cleaned up the drum and shoes with brake cleaner, sanded the shoes with 400 grit sand paper and wiped the shoes down again with brake cleaner. Still the brake is not so good. If I press really hard I notice some braking. The brake pedal adjuster is adjusted all the way. There is material on the shoes and the bmw repair person thought the shoes were ok.

The drum and shoes seem very smooth.

What to do? Use a wire brush on the shoes? Get new shoes, do I use 400 grit sand paper on the drum a bit, drag my feet and do a Fred Flintstone stop?
Thanks,

George

Re: What to do about rear brake?

Posted: Thu Jun 12, 2014 2:55 pm
by Bamboo812
I have read somewhere that once brake shoes are contaminated with brake fluid or oil it is impossible to ever get it completely out. That said, back in my broke VW owner days, I did what John Muir recommended in his "How To Keep Your Volkswagen Alive" manual; remove the shoes, soak them in white gas or Coleman fuel for an hour, set them on the ground and light them on fire. After they have cooled down, make sure the linings are still solid to the shoes, remount, and start saving for new ones. He also recommended breaking the glaze on the drums using a Brillo pad. Personally, I switched my stone hard original shoes for the ones sold by Vintage Brake. I can now stop my R75/5 using the rear brake only...

Re: What to do about rear brake?

Posted: Thu Jun 12, 2014 4:43 pm
by dwerbil
Rear brakes on my /7 weren't very good at all for stopping. I did the sandpaper thing and all to no avail.
I bought a pair of these....

http://www.jcwhitney.com/ebc-brakes-oe- ... 871y1977j1

...and now the rear brakes are fantastic. With a bit of effort, the brakes can now lock the rear wheel (which, of course, you don't want to do).

George, it's a simple formula....good brakes may add years to your life span.
Buy new brake shoes.

Re: What to do about rear brake?

Posted: Thu Jun 12, 2014 4:48 pm
by George inMinneapolis
Well then,

That's what I'll do.
The JC Whitney ones look ok.
Thanks everyone!

George

Re: What to do about rear brake?

Posted: Thu Jun 12, 2014 5:18 pm
by dwerbil
Just to add -- the new rear brake shoes work so much better, I'm riding the bike with much more
confidence now having way better stopping power.

Re: What to do about rear brake?

Posted: Thu Jun 12, 2014 5:37 pm
by Kurt in S.A.
What material are these EBC shoes? Is there the chance that they'll wear the drum surfaces faster than OEM?

Kurt in S.A.

Re: What to do about rear brake?

Posted: Fri Jun 13, 2014 12:24 pm
by George inMinneapolis
Hmmm. The JC Whitney link is for a 1977 R80/7. When I change the year in the parts selector to 1978, the page says the brakes do not fit my vehicle. I was not aware that there was a difference. If I entered 1978 R/100 the website says the brake is fine to order. But not for a '78 R80/7.

I can go to Bike Bandit and order these shoes: http://www.bikebandit.com/ebc-organic-b ... s?m=143979
They are EBC as well.

I suppose they are the same as the one's at Whitney.