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best way to "rough up" a glazed brake drum?

Posted: Sat Jan 28, 2017 8:06 am
by spudman
Last year as I was completing my model 99 Road Toad restoration project, I noticed that the inside of the front brake drum was exceptionally shiny and almost as smooth as glass. The front pads are new, but I don't seem to get much stopping power from that front brake at all. I suppose I might be use to the front braking capability of my K1600GT, but I'm wondering if scuffing up the inside of that drum to remove some of that glazing might help. I've been told that the scuffing should be done in such a way that the abrasion runs perpendicular to the direction of the pad, but I'm not sure of what method might be my best option. This surface looks quite hard, so any suggestions are appreciated! Thanks!

Re: best way to "rough up" a glazed brake drum?

Posted: Sat Jan 28, 2017 8:53 am
by thrownchain
If you're just deglazing you can just scrub the drum with some med grit sand paper. I personally don't believe that the direction makes a difference for that. And a light scrub of the shoes won't hurt either. Light being the operative word.

Re: best way to "rough up" a glazed brake drum?

Posted: Sat Jan 28, 2017 9:43 am
by viclioce
150 to 200 grit seems to work best for me. I do it any time I change pads. ; D Victor

Re: best way to "rough up" a glazed brake drum?

Posted: Sat Jan 28, 2017 10:43 am
by Zeek
Another good reason to vapour blast parts :D
Brings all these surfaces back to 100% brand new.
I guess the other way would be to bung it on a lathe and skim the surface.

Re: best way to "rough up" a glazed brake drum?

Posted: Sun Jan 29, 2017 5:41 am
by spudman
Thanks for the suggestions guys. I was actually wondering about the lathe option myself. Back in the day, people actually had drums cut (at least on their 4-wheeled vehicles) when they did a brake job. Today, new drums are so inexpensive that everyone just buys new ones. On a bike though, that's not practical, so I'm wondering if in fact it would be a somewhat easy task to put a fresh cut on the inside of that drum?

Re: best way to "rough up" a glazed brake drum?

Posted: Sun Jan 29, 2017 6:24 am
by thrownchain
Unless the drum is out of round or heavily scored, resurfacing the drum is over thinking it. Deglaze the drum with the sand paper and try it, if it works you'll know. Also remember that old drum brakes are not up to the braking capacity of new disc brakes. So there isn't a viable comparison there.

Re: best way to "rough up" a glazed brake drum?

Posted: Sun Jan 29, 2017 6:36 am
by spudman
Sounds good thrownchain. I'll give the sandpaper method a shot. And yes...I'm probably a bit spoiled by the performance of today's brakes and I may in fact be hoping for a little more than what is possible with the Toad. :)

Re: best way to "rough up" a glazed brake drum?

Posted: Sun Jan 29, 2017 12:23 pm
by michael_perrett
If you want to research brake drum tuning, go to the Vintage Brake site. Turning the brake drum has been for me, a accurate way of increasing effectiveness. The best way to do that is to turn the whole wheel, since the tight spokes can distort the hub/drum. My lathe cannot turn the complete wheel, so I have to settle on just doing the drum, before lacing the rim. After that is done, one can turn the shoes, while on the backing plate with a adjustable screw between the brake cam arm and the plate anchor. One can turn the shoes to a point that the shoe width is equal to the drum diameter, thus allowing the greatest contact area as well as new lining surface. Ed Chesnut's advice on centering the backing plate is the final assembly task.

Mike Perrett