Hello all, I have a 2004 4Runner with the hydroboost brake booster system. When the pump kicks on after the 3rd or 4th press of the brakes, I get the noise shown in the video. When I first turn the key to the on position and the pump starts, I don't get the noise. It's only after pressing on the brakes, engine running or off. It almost sounds to me like it's over pressurizing and it's like a relief valve. Almost like there is a sensor that tells the motor when to stop running (at a certain psi) and that its faulty. The brakes are hard in the morning before I turn the key, so all the pressure bleeds off somehow through the night. Is this normal? When I bought it, it wasn't making this noise. The only thing I've done to the brakes is change the two front lines to ss braided lines, followed by bleeding all 4 calipers. Another thought is that air worked its way up to the master cylinder area. My next thought was to try to bleed the brakes again. Any ideas?
Video: https://youtu.be/FQD77EiRUtI
Video: https://youtu.be/FQD77EiRUtI
