Frmmli

My 2014 ES 300H at 55,000 miles and prior did not have the sound and the sound was noticed around 60,000. It come on under moderate speed and moderatelyhard braking usually right at the end of the braking stroke or shortly after. I will not call it intermittent but rather at the right combination of speed and braking effort. The sound is like hydraulic fluid or air going through a restriction/orifice, like a noticeable 'urrrrp'. No pulsation to indicate activation of anti-lock brake. It is none of those normal stuffs like dry bushing, rubber boot, related to the pedal or linkage. One dealer said that is related to the braking system taking over suddenly from the Hybrid re-generation system switching out and the brake fluid rushing in. I do not buy that fully. I am also wondering is it started to happen after the 60,000 miles maintanance which include a replacement of brake fluid.