How much does it cost to repair a master cylinder?

Brake fluid level ever get low? IF the fluid has NOT gone low and pedal is going down to far... Possible master cylinder.. OR... Bypassing inside the ABS control unit... This needs to be tested before any parts are installed!! .. IF fluid has to be added frequently, have the system checked for leaks!!

if pedal goes all way to floor first check for obvious leaks or fluid gone, inside part of tire etc, if fluid is missing find leak and fix, if no fluid is gone and pedal goes down still, turn off car does pedal pump up and get hard? if so turn car on and watch it goto the floor, this means your power booster is bad best to replace booster and master cylinder because usuall booster damage comes from leaky master cylinder, if eveything else has been checked and even when off the brake pressure is not there, master is bad, master cylinder labor is a little over 1 hr labor for your vehicle