Prius 1.8 2010 ABS Motor Noice Problem

[RashidKayani]

just purchased prius a few days ago
after some days while driving i felt that ABS is not working
upon consulting from machenic's they advised the ABS unit replacement
i have done so, but now ABS is working but after every 3 brakes padles a perticular noice irritates me
so kindly suggest if you guys has any solution in this regard, thanks

[haseeb.basharat]

What type of sound it is?

[khuram2703]

I also come to know brake master cylinder failure in prius most of the priuses..May be the cars are mostly driven 200k and have tempered reversed meters.