Grabbing Rear Brake Drum

By Ren Withnell

4th August 2015

My Honda CBF 125 has a rear brake drum and for 40,000 miles it has worked just fine with occasional servicing and cleaning. Recently though it started to get squeaky, but that's not a problem. Then it became very grabby, dangerously so. Grabby? When I pressed the brake pedal and the shoes touched the drum it would lock up the rear wheel, the brake shoes would grab the drum. This made the rear brake like an on-off switch rather than a safe progressive method of controlled stopping.

I did not know what the problem was. I decided to strip the rear brakes to assess what might be afoot. When I removed the brake plate with the shoes attached I noticed the shoes had some kind of a coating on the contact face. I know what brake surfaces should look like and this did not look right. I wondered, is this glazing? I've heard of such a thing but as I've never had a problem with it I've never learned much about it. A brief search of some images soon confirmed my brake shoes were glazed.

Now that's what I call glazing...

Why? Another cursory search online does not come up with a definitive answer, just a lot of opinions. Too much heavy braking? Too much light braking? Binding brakes? Contamination? Incorrect run in procedure? Do brake shoes even have a run in procedure? And so on and so on. I am aware the shoes have been used heavily recently as I have been around Ireland with a full camping load and I have been practising using the rear brake more. Why? It's all to do with the gf preparing for her test, I'll explain elsewhere sometime soon.

So my shoes are glazed and this has caused the rear brake to become grabby. What's the solution? Sandpaper or emery cloth dear friend. Rub that glaze off and return the shoes to the original pad material beneath the glaze. After 3 minutes of rubbing the shoes were ready to be put back in. I can report the issue has gone and my brakes are working just fine after a short period to bed them back in.

What can I do to avoid this in the future? I do not know. Because as yet I have not found the definitive cause for glazing I cannot offer myself or anyone else any advice on how to avoid it. I'm sure the readers will have their own opinions and I'd welcome them in the comments below.

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