Brakes: from start to stop

Everyone wants to be first especially when it comes to new technology in the auto industry.  Anti-lock brakes is one such technology.  Referred to as ABS now the anti-lock breaking system is now a standard safety feature on all vehicles.  Back in the 1950’s this was on the wish list of all auto manufacturers. One German manufacturer boasted an electric 4 wheel anti-skid system as the first but an American luxury car actually got there first.
Anti-skid breaks was actually first used on aircraft in the late 1940’s.  Engineers knew they needed to develop an effective automotive anti-skid system with a fast acting electronic controls. Ford introduced a system call sure-track anti-skid breaks.  This was developed by Kelsey-Hayes for the Thunderbird and Continental Mark III in late 1969 which cost about $195.  This only worked on rear wheels and was made for the 1974 Continental Mark IV. 
While this rear wheel anti-skid system was a huge improvement, they were still seeking a better system.  With the rear wheel anti-skid system steering control was still an issue.  The idea of an all-wheel breaking system would be the “Holy Grail” of breaking systems.  This idea would give the front wheels the ability to maintain control without locking up.
That’s where the sure-break system for Chrysler’s 1971 Imperial came in, offering the first system to allow the driver to have steering control without locking up the breaks.  The Sure-Break option cost $351.50 on the Imperial, whose starting price was just over $6,000. 
They system worked like this, there was a sensor on each wheel, and in the trunk was an electronic control box. This was a three-channel system.  It used one break-pressure modulator for each front wheel and one modulator to control both rear-wheel breaks.  The modulators were vacuum canisters that operated cutoff and relief valves to stop hydraulic pressure from going to the wheels.  The anti-skid system, like Sure-break or even modern ABS doesn’t “pump” the brakes, instead maintains break pressure in a panic stop.  The system releases pressure in increments as lock-up is detected.
The auto industry is always evolving and improving.  Safety being the drive behind most improvements we can expect the future to bring many new exciting features!