9 April 2013

Anti-lock Brakes: Who Was Really First?

All carmakers like to tout innovations or “firsts.” Often, however, we find that a similar feature or function debuted many years before. In some cases, a good idea may have arrived before the technology was truly sorted out. In other instances, lack of market acceptance caused good ideas to be shelved for years.

Our first installment in this series looks at anti-lock brakes.

Mandated today as standard equipment on all new passenger vehicles, anti-lock brakes, commonly known as ABS, had been on automotive engineers’ wish lists at least since the 1950s. One famous German carmaker has long boasted of having the first electronic four-wheel anti-skid system. But an American luxury model got there first.

Anti-skid brakes first turned up on aircraft in the late 1940s. One of those purely mechanical systems, Maxaret, was adapted to the British Jensen FF, a four-wheel-drive version of the company’s Interceptor grand touring coupe, in 1966. Just 320 FF models were built through 1971, and this right-hand-drive-only model was not exported (officially) to the U.S.

Engineers recognized that an effective automotive anti-skid system would need to have fast-acting electronic controls. Ford introduced the electronically controlled Sure-Track anti-skid system, developed by Kelsey-Hayes, for the Thunderbird and Continental Mark III in late 1969 for about $195. The Ford Sure-Track system, which worked only on the rear wheels, was made standard for the 1974 Continental Mark IV.

The “holy grail” of automotive anti-skid technology was to also prevent the front wheels from locking up in order to maintain steering control during a full-brake panic stop. That’s exactly what the Sure-Brake system for Chrysler’s 1971 Imperial offered, despite a long-standing claim by Mercedes-Benz that its Bosch ABS system was the first electronically controlled four-wheel anti-skid system to reach production (1978 in Europe).

The Mercedes system probably had an advantage with more modern digital controls, but the Imperial’s Sure-Brake system, developed by Bendix, proved effective. The Sure-Brake option cost $351.50 on the 1971 Imperial, which started at just over $6,000. The option cost was reduced to $344 for ’72 and ’73.

A story published in Popular Science in November 1970, written by respected scribe and noted spy photographer Jim Dunne, described Sure-Brake in detail. The system had a speed sensor on each wheel, and, in the trunk, an electronic control box. Sure-Brake was a three-channel system: It used one brake-pressure modulator for each front wheel and one modulator to control both rear-wheel brakes. Modulators were vacuum canisters that operated cutoff and relief valves to stop hydraulic pressure from going to the wheels.

An anti-skid system, like Sure-Brake or modern ABS, does not “pump” the brakes. Rather, as the driver maintains brake pressure, such as in a panic stop, the system releases pressure in increments as lock-up is detected.

Did it work? According to Popular Science’s instrumented test of an Imperial equipped with Sure-Brake, the system provided “firm, steady stops – even when driving on glare ice.” The article cited a dramatic 40-percent reduction in stopping distance on slippery surfaces. That was a great benefit in itself, made possible by a two-speed braking-rate capability. A mercury switch in the computer could determine the surface friction, based on the car’s rate of deceleration, and then select the appropriate pulse rate.

That “pulse rate” and its resulting clunking sound could have frightened drivers into thinking there was a brake malfunction. In fact, the editors of Road Test magazine, which also tested a 1971 Imperial with Sure-Brake, cautioned about this very situation, stating, “In an actual panic stop you hear the clunk from Sure-Brake precisely four times a second. As this could add more juice to an already panicky situation, Chrysler wisely suggests in the owners manual that you practice with the system as soon as possible after taking delivery of the car.”

Did Chrysler salesmen pass along that wise suggestion, as well? Probably not.

If measured by sales, Sure-Brake was a failure, probably going on less than 5 percent of Imperials through 1973, so just a few hundred cars per year, at most. It did not return for 1974.

Some might want to blame the option’s price for the failure, but Sure-Brake cost less than a number of the Imperial’s other extras, such as the AM/FM stereo with tape player. As was often the case with new safety features, the manufacturer and its dealers probably failed to adequately market the technology and explain its benefits to customers.

As Road Test concluded, “At the very least, Imperial should be credited for pioneering what must be the ultimate in the current state of the art of braking as practiced by Detroit.”

Do you own a 1971-1973 Imperial equipped with Sure-Brake? Tell us about it.

23 Reader Comments

  • 1
    Henry Leach Sedona, Arizona April 10, 2013 at 15:17
    the 1971 Cadillac Eldorado was available with optional Track Master, a computerized rear wheel skid control system with a cost of around $250.00
  • 2
    Diane Brandon Oregon April 10, 2013 at 17:23
    I'm surprised this well-researched article didn't include the mechanical brake servo. Invented in 1919 by Marc Birkigt for the Hispano Suiza H6, Rolls-Royce licensed the technology immediately and kept using it through the Silver Cloud/Bentley S series in the 1960s. The servo "boost" works off the torque developed in the gearbox, and is very effective. The faster you are driving, the quicker you can stop. It's joked that if you sneeze on the brake pedal at high speed, the car will stop immediately, however when driving slowly into your garage, you can easily take out the garage wall because it's sometimes difficult to stop the car when it's traveling just a few mph.
  • 3
    Jon Block Rochester Hills, Michigan April 10, 2013 at 17:35
    The Tampa Bay Auto Museum (see www.tbauto.org) has an all-original 1964 1/2 Ford Mustang Coupe with a Ferguson 4WD system and also Ferguson's ABS braking system. It was a prototype developed for Ford, and apparently the $500 upcharge was not enough to convince Ford to put it into production. If anyone has any more information on this rare car, the Museum would appreciate hearing from you!
  • 4
    rollie newark,ny April 10, 2013 at 18:36
    I do not like anti-lock brakes. I know many others will not agree with me, but I prefer to control the braking proceedure myself. I live in upstate NY where snow and ice are commonplace. I know how to pump the pedal and the proper steering configuration when on icy roads. Anti-lock brakes, when engaged, scare the hell out of me. I plant both feet on the brake pedal and stand upright in the seat. It still feels as that the car doesn't want to stop. If I pull the anti-lock brake fuse, the system becomes de-activated, although a warning light will appear on the dash. I have, in 50 years behind the wheel, experienced many skidding conditions on NY highways, and have had many times to respond to slippery conditions. I have never slid into another car on ice, while I have gone by many others who have. Knowing how to drive in adverse conditions is a skill. Period. I realize many will villify me for de-activation of this system, but for decades there were no such systems, and people had to know how to drive, or stay home. There are many times the anti-lock system will actually work against you. Perhaps the most prevelent is on sandy or lane specific dirty conditions. So, let the assault on me begin, but the fuse will stay in the glove box until trade in.
  • 5
    howard la rose naples fl April 10, 2013 at 19:18
    I sold cadillac at Lorber Cadillac in ea providence ri I think the name was SFETY TRACK customer did not like that you could push brake to the floor with the engine off and low pedal with engine on.
  • 6
    martin benade Cleveland OH April 10, 2013 at 22:31
    Actually modern ABS DOES pump the brakes. It rapidly releases and then reapplies the braking hydraulic pressure, just like you can do with your foot. The difference is that the speed sensors tell it what to do (usually) more cleverly and much faster than us humans can do
  • 7
    Mark Bardenwerper Wisconsin April 10, 2013 at 23:44
    The Citroen DS, introduced in 1955, had inboard disk brakes (the first in a four door sedan) and a proportional braking system that was not a true antiskid, but was load sensitive front and rear. The cheaper ID later had a simpler system that controlled brake effort only to the rear wheels based upon the amount of pressure in the rear hydropneumatic suspension.
  • 8
    Daniel Risz cave creek, az April 10, 2013 at 12:04
    The Maxaret system was first installed on large transport aircraft in the 50s. It's a simple and effective, but does add some unsprung weight
  • 9
    Steve Y Middletown, MD April 11, 2013 at 18:11
    I owned a 1973 Thunderbird with Ford's version. The few times I had to panic stop that 6,098 pound beast, it sounded like it would shake the car apart forcing me to relieve some of the braking pressure. Maybe that is what the designers had in mind! I have always been a downshifting advocate. After my first few automatic transmission cars, I swore off and went to manual only for daily drivers from 1986 until 2012 when we got a Prius. The only exception to that has been my '67 Firebird with the bullet-proof TH400 I have had since 1998.
  • 10
    Mac Ballard Central Florida April 11, 2013 at 08:01
    I have owned six Lincoln Continental Mark III's. The Sure-Track system was standard on the 1971 Mark III as was a lot of previously optional equipment. This offering of a comprehensive list standard equipment was presented as part of their celebration of the 50th anniversary of the Lincoln Motorcar Company. It did indeed make a lot of noise when operating, and like the Imperial it cycled at a much slower rate than a modern ABS system. On dry surfaces it may have slightly increased stopping distances, but on wet or snow covered roads the improvement was obvious. The impression on ice was that not even "modern" technology could save you although it did keep you slip, sliding away in a relatively straight line. The system was designed to cycle once at engine start up as a test and you could hear it every time you started the car. The actuator was ahead of the passenger side toe board and looked like a small vacuum brake booster with small master cylinder. The electronic control unit was located under the glove box liner. The early system has a sensor on each rear wheel and operated if either wheel locked, the later system had one sensor on the differential and operated only if both rear wheels locked.
  • 11
    Jim Skelly Dearborn April 11, 2013 at 09:23
    GM offered the anti-skid braking system on 1970 models. Cadillac called it Track Master, while Buick called it Max Trac.
  • 12
    Jeff Stellish Okoboji, IA April 11, 2013 at 11:41
    My grandpa, Wayne Stellish, bought a brand new 1972 Imperial LeBaron in December, 1971. He got all the options, every bell and whistle including AM/FM tape and Sure-Brake. The Sure-Brake system has always performed flawlessly and still does to this day. We lost Grandpa last February, but still have his Imperial alongside his 2005 Chrysler 300C AWD. The Imperial only ever had basic maintenance performed, with no major repairs ever. Still functions flawlessly and is in remarkably good shape.
  • 13
    Todd Appel St. Louis, MO April 12, 2013 at 08:13
    We had a 1975 Chrysler Imperial that had 4 wheel disc anti lock brakes and the car stopped in the distance of a bus from 40 mph in a panick stop.
  • 14
    Dennis Depew Neodesha, Kansas April 17, 2013 at 09:11
    My parents ordered a 1972 Imperial LeBaron sedan, black on black with all options. The Sure Brake option was awesome. Our dealer did take us out on our small town's airport runway in snow to demonstrate the system. The rapid fire clunking was very disconcerting at first but the system did work as advertised. That system saved our bacon more than once over the 6 years we owned that car.
  • 15
    Douglas Bain Ann Arbor, Michigan April 18, 2013 at 13:48
    I worked in the Chrysler Brake Department at the Chrysler Proving Grounds in Chelsea, Michigan at the time the Sure-Brake ABS system was being developed for the 1971 Imperial, but I did not personally work on that project. While Bendix did indeed manufacture that system, it was a join development program between Chrysler and Bendix. Many of the toughest development issues were resolved by Chrysler Brake Engineer Joe Douglas and Chrysler Brake Technician Joe Geer. Without those two, the Sure-Brake anti-lock system would never have seen the light of day. Bendix deserves the credit for manufacturing it, but those two deserve the credit for making it work.
  • 16
    Tim NJ April 18, 2013 at 15:04
    My father had a 1974 Imperial. (dreadful build quality) that had 'Surebrake" in it, so it may have been available into the 1974 model year. I was about 13 years old when he got it, and he sold it before I got my license.
  • 17
    James Myers Fillmore, California April 20, 2013 at 02:34
    My Father and Mother owned a 72 Imperial LeBaron Sedan equipped with the Surebrake system. That car was nice! They kept it until 1983 when the Chrysler New Yorker Fifth Avenue came out. I should have bought their 72' Imperial because it only had 33,000 original miles and the car was flawless inside and out as all of my Parent's cars were.
  • 18
    Allen Wieber Louisville, Ky April 25, 2013 at 15:39
    I don't care what any body says. A panic stop on dry pavement with ABS will take a longer stoping distance than the same car with out ABS. Don't believe me. Try it for your self. The friction of a locked up tire on the pavememt will stop you faster. You may skid but you missed the impact with the other vehicle. ABS is a joke on dry pavement. I live in a place where the roads are not wet or have ice most of the time. Why isn't there a on off switch so the owner of a vehicle has the option to turn the ABS off while on dry pavement and on for slipery pavement? Oh, sorry that is too simple!
  • 19
    Peter Lucas Tanzania, October 28, 2014 at 06:23
    The main problem of ABS brake system come since many user doesn't know when do they have convertional brake ,and when the ABS is engaging , there would have been an instruction as a guideline , how does ABS activated, in which driving conditions, since ABS is just like a branch of tree then user they must have a great deal of understanding the system, ABS reduces tyre busters , tyre pre maturing wear and its illuminates the noise when you suddenly stop at high speed, it has its own behaviours and characteristics, Then if the user gets close to the system they will easily control it, and they won't find it hard to drive in the ABS cars , Allen wieber has make it so clear it would be the best idea to have a manual switch to diactivet the system at some driving conditions,
  • 20
    Gary Kowalski South Bend, Indiana July 14, 2015 at 22:41
    I'm somewhat late to this discussion, but I just found this while doing some research. In the mid 1970s, I was fortunate enough to befriend Del Elliot who was in charge of the ABS division at Bendix here in South Bend, Indiana. With a team of workers from Bendix, we ended up with a Chrysler ABS system (Bendix said that it was for "Adaptive Brake System") in a 1970 AMC Hornet pro rally car that had won it's class in the 1971 BC Centennial Rally (later named the Sell 4000 Trans-Canadian Rally) and competed in the SCCA Pro Rally series for most of that decade. We were actually pushing the ECU beyond standard road settings and were just about to re-engineer it when Bendix decided to cancel the project. I still have the car and the ABS is a great talking point (in addition to its rally history). I'd love to connect with anyone who has memories of this car.
  • 21
    Bob Dangler Hastings, NE October 29, 2015 at 20:03
    I worked in the Brake Engineering Dept. in Highland Park during the development of the "Anti-Skid" system. To me it was a wonderful system. A special very slick material was found that you could not stand up on - you would fall down. it had been developed for crowd control. The system enabled the car to be steered through pylons while full on the brakes. This was pretty unheard of at the time! My Supervisor at HP was Jack Thon. I wonder what ever happened to him. My main function was to fit the necessary components in a vehicle whose available space under the hood had already been pretty well used up. Ended up putting the actuators between the fenders and inner fenders. Woe the mechanic that had to work on them! There was a sensor at each wheel that sat just adjacent to a wheel with milled teeth on the periphery. This provided the "count" that told the computer whether that wheel was slowing down or not. If I remember correctly, the computer was of the electron tube type without modern electronics. This was less than ideal. Thanks for bringing back a lot of memories for me! Bob Dangler
  • 22
    PinkMango Florida January 26, 2016 at 13:44
    I'm surprised that the mass-introduction of ALB on the Honda Prelude was not mentioned. In the Honda sales end of the auto industry, the story is told that Honda's introduction of ALB on the Prelude (included, not sold as an option) was the first mass production of an automatic braking system that was promptly stolen and turned into ABS.
  • 23
    bobbobbob bobbob September 20, 2016 at 05:49

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