Brake pedal "throbbing"

[smokinttype]

It seems lately that what I got to use my brakes the peddal throbbs under my foot, kinda feels like its surging or something. Is this the accumulator bowl? or is this the electric motor in the power master unit going out?

 

[TurboToy]

does it do this while driving or just sitting still? if while driving you may have warped rotors and or drums sitting still you may be right about the power paster

 

[smokinttype]

nothings warped just the pedal is hard for a second then it kinda eases down, im hoping it is just the accumulator bowl....anyone else?

 

[Drewster]

when im parked and with my foot on the brake, i can hear my power master pump running. (a quiet humming/hissing sound) it runs for approx, 5 sec. every 30-45 sec.
a similar sound may be in your car and coincide with the pulsations.
FYI ....autozone makes a rebuilt powermaster for cheep! it comes out to cost a little more than a accumulator bowl.
my friends GN needed an accumulator. i gave him a spare one i had cause i wouldnt drive it with the brake pedal going to the floor. it stiffend up the pedal quite a bit. i dont remember if it was pulsating or not.

 

[smokinttype]

Thanks! My brake light comes on and goes off.....I am going to try a new accumulator bowl and see how that works out for me. I dont really want to replace the WHOLE thing but if I got to I go to...