Anti-Locking Braking System (mechanical-hydraulic)
The first anti-locking braking systems go right back to 1928. Therefore, it should come as no surprise that parallel to the electronic-hydraulic system, a mechanical-hydraulic method of solving the problem also appeared. This was put into practice in the Ford Escort, a front-wheel drive car with a diagonal brake-circuit system. Indeed, only for a short time, and then never again.
On the final drive, where the axle drive shafts are connected, two shafts are driven, each by a toothed drive-belt. The two shafts are friction-connected to two flywheels. The principle of these pressure modulators is based on the fact that the respective flywheel slips if the braked wheel suddenly blocks. If this occurs, it can trigger certain actions.What happens then, is the same as with an electronically regulated ABS-system, except that here, the brake line between the brake pedal and both wheels (e.g., front-left and rear-right) when threatening to block, is interrupted and perhaps even pressure taken off and returned. In addition, the belt-driven shafts each contain an eccentric and a pump element.
Thereby, in fact all the wheels can be regulated at the same time if they threaten to suddenly block. However the rear wheels are dependant on the front wheels. Their individual blocking tendency is not picked up by the system. The biggest disadvantage of the system was however, apart from the complexity, the relatively slow regulation cycle. Electronic systems manage 10 cycles/sec., the mechanical systems only 3. 05/10