I have worked in the automobile business for a living since 1952, when I realized that I was so much smarter than my teachers, particularly my Latin teacher. It took a while to realize that maybe they actually had something going for them, and they really were smarter than I was. Before I joined the Ford dealership in Toronto, I had worked before that on afternoons and Saturday at a gas station that was positioned about half way between my home and the high school. In 1952, I joined GM in Oshawa Ontario, and spent the next 30 and a half years with them primarily with the Service department. So now you have a bit of my history and where I come from.
Over that time I heard on may occasions the phrase “They don’t make ’em like they used to”. It was true too, but not in the sense it was said. The fact is autos have been different and better in nearly every year since the Second World War. Some improvements had been made prior to then, but the biggest and most important ones were post war. Prior to the war, hydraulic brakes had just become mainstream, and prior to them we had something called “Rod” or “Cable” operated brakes. One big advantage of hydraulic brakes is that the braking pressure is always equal reducing the tendency for pulling brakes. Rod and cable brakes required frequent adjusting to keep the pressure on the brake shoes approximately equal to minimize the pulling mentioned before. So it was that brakes were now self equalizing.
Automotive brakes were pretty primitive in the old days. I remember that a 1928 Chev that had something called “External Contracting” brakes. What this mean was that the brakes consisted of a drum at each wheel, which rotated with the wheel. It had a strap or band around the outside of this rotating drum that would bind onto the drum when the brakes were applied. They worked, sort of, if the aforesaid rods were properly adjusted! But if the car was driven through water and it splashed on the band or brake lining, you could heave on the brakes all you liked but the wet linings had no friction and it took a 40 acre field to stop.
Just before the war, the system changed to a hydraulically actuated “Internal Expanding” brake shoe and drum, where the shoes expanded inside the drum and provided the necessary friction to stop the car. The drum was still on each wheel and rotated with it, but the shoes were now inside the drum, protected from the weather. This worked quite well, and while brake adjustments were less frequent, since they now needed to be adjusted for wear; the rods and cables were history except for the Emergency brake as it was called then. There were 2 forms of the internal expanding and one was a product put out by the Bendix people that was referred to as Self Energizing. The design here was that the brake shoes inside the drum were “full floating”. The leading edge of the primary brake shoe would contact the inner surface of the drum in the forward motion when the pedal was applied, and the friction would push against the trailing shoe or secondary one. That shoe was anchored to a large fixed pin on the backing plate and all the braking friction was applied to the shoes and then to the pin. It worked quite well, but still had problems of poor or no braking if the linings got wet.
The aforementioned Emergency brake became the Parking brake when it was determined that if anyone yanked on the Emergency brake at any kind of speed, the operator could find himself in a dangerously skidding and out of control car, VERY quickly. My car a 2012 Buick Verano has eliminated the parking / Emergency brake as it once was. This one works by having the ignition on, and the foot brakes applied, and you push a button. One releases this brake by reversing the procedure.
Chrysler was likely the first manufacturer to adopt a form of disc brakes in the early 5o’s as I recall. It was a complicated thing at the time and while it worked it had a problem, the emergency brake could not be connected to it. A separate brake operated by a cable was needed to make it work. Chrysler dropped the thing but it started the trend to discs on everything. Disk Brakes are very common today, and give very good straight line braking. As they grew in popularity on cars, they were installed on the front wheels only, and eventually they wound up on all wheels. The old drum brakes were less expensive to produce, hence the popularity with manufacturers. Discs are also self-adjusting.
Disc brakes are a far cry from the old brakes, and are very necessary with the high speed that vehicles can reach today. They have a Caliper that clamps a disc pad to a turning rotor, and only relies on driver pedal pressure to stop the car. Power brakes are standard equipment today as well, and that allows a multiplication of the drivers foot pressure to be multiplied to the hydraulic system. One problem still remained and that was in the material used for the friction surface of the replaceable brake lining. It was based on an asbestos formula to withstand the heat of stopping. It was replaced with a metallic lining and it took a lot of work to eliminate the noise these made. But today it has happened.
Today, cars have a few extras that could only have been a dream way back when. Anti-lock brakes were the first, and were only practical after disc brakes and power brakes were common. An on board computer detects that a brake is locking up and the computer overrides the driver applying and releasing the brakes VERY quickly, allowing the vehicle to still be steered while it is slowing. (You cannot steer wheels that are locked).
Following that, a computer now detects for Traction Control, and it will kill engine power, and at the same time apply the anti lock brakes to allow the power in a start stop manner to the wheels, much faster than is humanly possible. An even newer system is Stability control, and this comes in to play if the vehicle sensors detect that the car is going to spin or roll over, and takes over the throttle and braking system to allow the individual wheel to brake and stabilize the vehicle.
While the original idea of brakes hasn’t changed at all. We still apply friction to the rotating part to stop it. But as you can see, it has become light years more complex as materials improved along with metallurgy, and the advent of computer control.
They don’t make ’em like they used to, and that’s for sure. Thanks to a lot of great engineers for all this.
This discussion all came about because I was speaking with some folks who were bemoaning the cars of today, and a video of a 1959 Chev in a head on collision with a 2012 Chev. The test was run and photographed by the insurance industry. Crash test dummies showed that if it had been real live drivers, only the driver of the 2012 would have survived, and he would have had a slightly injured knee. The other driver would have died instantly! Those big old heavy boats of cars are not as safe as one would think.
Over the next little while I will take a closer look at some of the other improvements to the cars of today, it is simply amazing.