Fig. 4 Wheel Speed Sensor

Fig. 5 Controller Anti-Lock Brake (CAB)

normal. These characteristics are discussed below. More technical details are discussed further in this section.

PEDAL FEEL

Since the Bendix Anti-Lock 6 Braking System uses the conventional Booster/Master Cylinder. The brake pedal feel during normal braking is the same as conventional Non ABS equipped cars.

When Anti-Lock is activated during hard braking due to a wheel lockup tendency. Brake pedal effort will increase do to the master cylinder pressure being

isolated from the brake system. Some brake pedal movement and associated noises may be felt and heard by the driver. This is normal of a Anti-Lock Braking System due to pressurized fluid being transferred to and from the wheel brakes.

ANTI-LOCK BRAKE SYSTEM OPERATION

During Anti-Lock Braking, brake pressures are modulated by cycling electric solenoid valves. The cycling of these valves can be faintly heard as a series of popping or ticking noises. In addition, the cycling may be felt as a pulsation in the brake pedal, although no pedal movement will be noticed. If AntiLock Operation occurs during hard braking, some pulsation may be felt in the vehicle body due to fore and aft movement of the suspension as brake pressures are modulated.

Although ABS operation is available at virtually all vehicle speeds. It will automatically turn off at speeds below 3 to 5 mph. Wheel lockup may be perceived at the very end of an anti lock stop and is considered normal.

TIRE NOISE & MARKS

Although the ABS system prevents complete wheel lock-up, some wheel slip is desired in order to achieve optimum braking performance. During brake pressure modulation, as brake pressure is increased, wheel slip is allowed to reach up to 30%. This means that the wheel rolling velocity is 30% less than that of a free rolling wheel at a given vehicle speed. This slip may result in some tire chirping, depending on the road surface. This sound should not be interpreted as total wheel lock-up.

Complete wheel lock up normally leaves black tire marks on dry pavement. The Anti-Lock Braking System will not leave dark black tire marks since the wheel never reaches a locked condition. Tire marks may however be noticeable as light patched marks.

VEHICLE PERFORMANCE

Anti-Lock Brakes provide the driver with some steering control during hard braking, however there are conditions where the system does not provide any benefit. In particular, hydroplaning is still possible when the tires ride on a film of water, resulting in the tire leaving the road surface rendering the vehicle virtually uncontrollable. In addition, extreme steering maneuvers at high speed or high speed cornering beyond the limits of tire adhesion to the road surface may cause vehicle skidding, independent of vehicle braking. For this reason, the ABS system is termed Anti-Lock instead of Anti-Skid.

SYSTEM SELF-DIAGNOSTICS

The Bendix Anti-Lock 6 Brake System has been designed with the following self diagnostics capability.