Breake modulator valve??

[jstanctb]

Dealer has replace front rotors and pads twice, turned drums and replace rear break shoes......

After about 1000 miles the break fluid system begins to modulate. Slowly at first but with additional miles the vibration increases. Originally thought that the rotors were warped. Now i think it is a fluid pressure problem.

When i depress the break shoe there is no vibration at that point. The front wheels do not pull to any side. Breaking tracks in a straight line.

What controls and regulates fluid pressure to the calipers?

 

[Mazda]

Bad Master Cylinder. Will give you brake problems like that.

 

[adsm08]

So wait, you have a pedal vibration during braking?

 

[RonD]

I read he has a brake pulsing while not braking, braking causes pulse to stop.

Could be worn wheel bearings, jack up wheel and see if you can wiggle it.
Spin the wheel and see if it spins true.

 

[adsm08]

I don't actually have a clue what he said. I am just guessing.

 

[tmcalavy]

No way of knowing until he responds...I read his post to mean he has a pulsing/modulation in brake system while rolling, but it stops when he applies the pedal...also new shoes/pads/rotors. Sounds more like a drivetrain or suspension demon rather than brakes, but who knows without more info.