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RALLYE USED BRAKE DRUM INFO - page 1 of 4

Why all this writing? Determining what is a "good" used part or a "bad" used part is debatable. I could just sell used drums with no comments. I think it is better for you to know what is what when you are looking to save a buck in your repair/restoration.

You have to remember that old cars are dangerous. They can kill you. Driving them; working on them; they are not 2016 vehicles; they aren't as safe. This is something you need to accept if you have an old car. They're definitely more fun, like rock climbing or cycling or any other endeavor we undertake other than hiding under the bed. Used parts are used parts; they are old; they can break; they can fail. New parts can have defects as well; and once you mount it on your car; your "new" part is now a USED part.

Don't quote me on any of this as I am not a brake engineer. Use these facts, opinions and conjecture at your own risk. Do your own research; form your own opinions; I am only reporting what I have observed in 44 years of playing with these roadsters. Take any information on this page with the proverbial grain of salt. I tried in the 70s to get "official" specs from Nissan on the minimum thickness of the rotors, ball joint clearance maximums etc.; and was never successful. One of the letters I received that I wish I had kept and framed said something like "They should be replaced when worn to a suitable amount".

Drums too thin can have strength and heat retention issues leading to warping, cracking and brake fade. (I've never seen a cracked one.) Also; the more the diameter is increased; the more the curvature (arc) over where each brake shoe contacts the drum is altered. Eventually; the shoes are only making contact in a limited area of the drum. In the past this was handled by "arcing" the shoes; a procedure done by automotive machine shops or some auto repair facilities. This isn't done much anymore unless the shop has specialized equipment to handle the release of possible asbestos laden brake shoes.

As a result; the braking done by the rear wheels is reduced somewhat. The shoes will wear faster in certain areas but will "fit the arc" better after some time. A single cylinder system as found on the rear of the roadster doesn't work properly anyway; compared to a dual cylinder setup. We are also talking about a VERY small difference; as even a plus .060" diameter drum is only .030" larger in any specific area of the drum. Also keep in mind most of the braking action is done by the front brakes.
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