Prius 2011 Brake Sound in Parking mode and When Stopped

sounds right to me, but i'm no expert. how many km on her?

 

sounds like it. strange that there are no codes. she using tech stream?

 

Techstream is Toyota's proprietary sofware, for diagnostics and so on. I'd maybe just continue to monitor, considering there are no lights/codes and the repair is likely to be expensive. Did the mechanic quote you a price for the repair?

Have the brakes been regularly inspected/serviced? Every two or three years the calipers should be pulled off the rotors, the caliper pins relubed with proper lubricant (Toyota makes a special lube for caliper pins, and there are some aftermarket lubes that are appropriate), the pads and shims should be cleaned up and relubed sparingly, at contact points. Anti-seize compound is the common name for the lube usually used for that.

It's best to "put the car to sleep" when taking the calipers off the rotors, by disconnecting the 12 volt battery negative cable. If the car is "live" there's a possibility of the hydraulic system pressurizing, which could push a piston right out of the caliper. Opening driver's door in particular will do this.

Also, when done, and before reconnecting the battery, it's good to press the brake pedal multiple times, ensure there is no excess travel. If excess travel is detected the car could display error lights, and it's best to avoid having to deal with them.

One further caveat: when reassembling rear brakes, it's imperative that the pin on the back of the pad that contacts the caliper piston be between the spokes on the piston face, and firmly seated thus. The piston should be rotated to ensure this.

Attached is the Toyota Repair Manual brake section.

Maybe also try a brake fluid replacement first? Toyota USA says nothing on the subject, but Toyota Canada says every 3 years or 48,000 kilometers, whichever comes first.

It is relatively easy to do, and can be done without Techstream. Here is a video:

Nutz About Bolts Prius Maintenance Videos | PriusChat
(video #18)

And attached is an instruction from the Toyota Repair Manual. Again, this is a Toyota sanctioned method that does not need Techstream. It does however require the car to be in a special "invalid" mode, which both the attachment and the video show. The video is easier to understand though.

I managed to do this myself with our car; my wife pushing the brake pedal to push fluid out. I did not have any motorized suction, just used a syringe at the beginning, to take fluid out of the reservoir.