Guys, it's classic symptom of ABS(EBD) activity , worn or differently worn tyres, even worst if they are different brand/dimension, uneven pressures on one axle, etc can cause this without being a problem with the system but sensor missbehaviour can cause that too
QUOTE: WABCO - Hydraulic ADD-ON ABS system:
EBD operates in forward and reverse and is automatically enabled whenever the ABS modulator is in the normal braking mode at vehicle deceleration rates of 0.3 g and above (i.e. medium to high brake pedal loads). EBD operation is similar to that of ABS, but is calibrated to intervene at lower wheel slip limits and operates the brakes in axle pairs instead of individually.
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Operation of EBD is detectable from a stiffening of brake pedal movement as the inlet solenoid valves close and a slight pulsing of the brake pedal as the inlet solenoid valves open. EBD operation ceases immediately the brake pedal is released.
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