If you know how to bleed brakes, then changing the master cylinder is an easy job, my pedal started to get nasty a while back, and was sinking to the floor, it was leaking from the seal where the pedal activates the master cylinder, it only took me just over an hour to install it, and a bit of time to bleed the brakes back up ( took longer to teach the wife to help with the bleeding of the system than it did to put the master cylinder on ).