Active and driver aid technologies were banned in 1993, however the use of hydraulic controls was not fully outlawed. Exposed by Peter Wright’s excellent book on the 2000 Ferrari, teams were still using a hydraulic brake bias control post 1993.
As an avid collector of F1 car parts (have you got any for sale?) I noticed a Japanese Collector selling a Jordan 197 brake pedal, I could immediately tell it wasn’t any ordinary pedal, as the bias mechanism had hydraulic lines hanging from it.
Once purchased for my collection, I was able to inspect and research the item. It was an electronically controlly brake bias mechanism. Gary Anderson was understated about the item, simply replying to me “you’d be surprised what technology we had at Jordan in those days” but other people behind the scenes told me a lot more about this hydraulic bias mechanism.
Under braking, teams want the brake bias to change as the car’s weight shifts and downforce is shed from the reducing speed. This can be done with the geometry of the master cylinder and the bias mechanism, but that would be a fixed geometry and hard to tune for different situations. So back at the time, teams were playing with a hydraulic actuator to alter the bias as the car brakes, as this wasn’t an active open loop system, it wasn’t a driver aid, being closed loop the system still remained legal until eventually outlawed.
This system was designed by Sam Michael back in the day when Jordan were a small team and all of the engineers retained a hands-on element, designing as well as race engineering.
It’s based around carbon fibre brake pedal, matched to the throttle pedal, also made in carbon. On the back of the pedal the usual bias bar arrangement was augmented with a hydraulic piston, which moves the bias bar in the same way as a mechanical arrangement. This was connected to the cars high pressure hydraulic system, and via a Moog valve was controlled by the car’s Chassis Control Unit (separate from the Engine control unit back in those days). The black bracket fitted to the left of the bias assembly mounts a sensor (not fitted here), which detects the movement of the system. Weighing over 800G its quite heavy compared to a basic brake pedal.
As a braking episode occurred the software would alter the bias from a preset “look up” table of values, altering the bias of braking from front to rear. It did this by moving the bias bar passing through the pedal structure. Fittings on the end of the bias bar, attach to the master cylinders, each one responsible for either the front or rear braking circuit.
It was theoretically possible to make the system a faux form of ABS, by altering bias away from one axle as it locks up, but this solution was never implemented, as it was still a solution maturing for its primary purpose, not to mention the dubious legality of a bias driven ABS set up.
Initially the part was made with aluminium fittings these were later upgraded to titanium, thus the part I have here is an early version of the system. The pedal itself is marked with “No2 28/5/97”. Its just 100mm wide, with pedal length of just 210mm.