Well as much as I love drum brakes on the big truck, I do have to admit they do not have full backing plates and they probably expel a lot of brake dust out of the back of the drum.
Don was an engineering manager of advanced development at the former GMās Delco Moraine Division in Dayton Ohio when I met him. I worked as an advanced suspension engineer for a division that was combined with Delco Moraine and as such worked in the combined advanced development group with Don. Don was a pretty innovative guy but heād cut his teeth on drum brakes and would try to re-introduce them long after the rest of the world had moved to disk brakes. A product out of his group was an electrically actuated drum brake with a ball-screw actuator built into the drum to actuate the shoes. Far, far better than your basic electric trailer brake and it was not backdrive-able so it could be used as a parking brake actuator as well. At a tech show I hosted, everybody asked when the disk brake version would be available because they didnāt want the drum!
The electric drum brake went into the GM EV-1 along with a similar system to apply the front disks, hydraulically, but in proportion to the re-gen available for this electric car. Brilliant guy but hard-headed.
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Perhaps if the drum had spokes instead of a solid bowl shape, leaving the innards exposed to airflowā¦
Ha ha, I kid! 
I hope we arenāt getting to the point where weāll need to install garbage bags over the brakes and then have them treated as hazardous waste. The last drum brakes I worked on some years ago, I broke my tool and I have no intention of ever buying another one. Disc brakes all around or Iām not buying the car-unless it might be a 1960 Morris Minor or something. Then Iād have to weld the tool up again or something.
Yup!
Back in the ā70s, it was SOP for Consumer Reports to indicate just how badly undersized the tires were on new cars that they tested.
While I canāt recall the exact GM models, I recall that there were several that were already at their tiresā rated weight capacity with just a driver onboard.
Add a few passengers, and you were pushing your luck, although most car owners were blissfully unaware of that reality.
Take a vacation trip with several people and their weighty luggage andā¦good luck avoiding a blowout.
Thereās another reason drum brakes are prone to fading; they donāt dissipate heat anywhere near as well as discs do!
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I remember back in the 60ās I believe when they came out with the drums with the fins on them. Not sure what good it did but they looked cool.
Anything that increases the surface area of the heat-dissipating surfaces (which the fins did) helps, but they simply cannot dissipate heat as well as a disc brake system. In a drum brake system, the shoes, their hardware, the brake cylinders, the pads, and even most of the drums are contained, in a disc brake system everything is open to the passing air, including the calipers (which are in effect equivalent to a drum brakeās brake cylinder).
Disc brakes are simply a better system. Stopping a vehicle is, in its essence, converting 100% of a vehicleās inertial energy into heat energy and dissipating it (cars with regenerative brakes excepted). The better the system dissipates the heat is the better itāll work.
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Thereās more to it than that. Drum brakes are inherently self actuating and they rely on that self actuation for a lot of the braking force. When the brake shoeās coefficient of friction goes down either due to overheating or getting wet, the loss of self actuation compounds the effect.
Disk brakes also fade, but a 20% loss of friction results in a 20% loss of braking, or having to apply 20% more force to do the same braking.
With a drum brake, that same 20% loss of friction also causes a 20% loss of self actuation and this results in a dramatic loss of braking. Less friction X less force on the shoes because of the loss of self actuation = brakes going completely away as opposed to simply being less effective in stopping.
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This was GMās attempt at high performance drum brakesā¦
Didnāt really catch on. Looked very cool, though.
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āever lastingā drum brakes
You have GOT to be kidding
My Grandma ,with the driving permit,knew to do this .
Knew to do what?
My 1953 Chevrolet, the one I drove in my crazy years, had drums. I did not call them brakes. I called them impeders, because that is all they did, impede your speed.
I did once experience brake fade on the disc brakes on my 2002 Sienna. Between Tlaxcala and Puebla, in Mexico, there is a four lane divided highway. Every so often there is a speed bump. If one has any place to go today, as opposed to a sight seeing expedition, one leaves a speed bump full throttle and keeps it full throttle until heavy braking for the next speed bump.
I got fade after quite a few of the heavy braking maneuvers. Scared me silly. I never even heard of fade on modern disk brakes. When I told my Son-in-law, he ordered racing rotors and put them on. No more fade.
Hey Bing what did one of the previous posters mention?Drying your wet drum brakes out.
OK, I get it. I even do it coming out of the car wash with disc brakes. On the first application of the brakes you can tell they are wet.
I remember when Buick introduced the finned brake drums to dissipate heat more rapidly. Buickās Dynaflow transmission provided little engine braking, so back in the 1950s, the Buick needed all the stopping power of the brakes it could muster ā hence the finned drum brakes.
When there was a demand for reliable braking performance, we have front disc brakes. When asbestos was deemed carcinogenic, we switched to metallic pads. If heavy metal brake dust is contaminating our fresh water supply, perhaps we should use something more organic such as carbon carbon instead of returning to inferior drum brakes that are not up to the job.
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So, instead of replacing brake pads with modern materials, such as ceramic or carbon, the natural solution is to replace them with drum brakes??