Tuychi,
Sorry to hear your problem with brake pump. My priusC 2012 was generating high braking sound whenever I applied brake and this only happened whenever it rain be it small or heavy rain. For past 3 regular services I have informed Toyota SC on this problem and each time they mentioned brake pads are still in good condition. As the sound get unbearable I insist Toyota SC to change the brake pads at front wheels initially but the sound was still there but volume was lower. I then insist to also change the brake shoes at the rear wheels. The sounds totally gone after that !. Had suffered with this sound for almost 1.5 years and this blurdy Toyota sc guys keep on telling me the brake pads are not the problem. I’m really doubting the quality of the technicians at Toyota SC now ! Recently I had the same unprofessional experience the Toyota SC in handling the my PriusC third brake light. What I am saying is Toyota SC may not be giving the right info do get opinion from outside too.