i have a 1989 190e that i got from my brother for my kid. as soon as i got in it to drive to Ohio from DC i noticed in his parking lot that the brakes would pulsate at slow speeds 15 mph or slower. i didn't realize then that the brake system was also making a noise like it was actuating.
well anyway i asled him about the pulsating and he said it had done it since almost day one when he bought it new.

i have recently been trying to figure out the exact culprit of this problem so i can fix it once and for all. i put new brakes and rotors on and it really didn't change things much if at all, but i have noticed wahat sounds like a pump cycling off and on when riding around at slow speed with the radio off.
this pump makes a whirring or whooshing sound that corresponds to the brake pulsation i think.

buttt what part is it that is making this pump switch on and off at slow speed???
i don't have a problem replacing it i just need to know what "IT" is lol

thanks all
gordon