Master cylinder diy?

[215kid]

Is there a master cyclinder diy floating around anywhere? I tried searching but didn't find anything. Is it hard to do? I can't imagine it to be. I had a leak on my driver side behind my front tire and in front of my rear tire. I took it to an indy to fix my door which turned out to be the lock actuator. They fluched the fluid because they said there was red fluid when they went to bleed the brakes. 2 liters to flush and bleed? And was charged over 550 to fix the door and flush the brake fluid. They said the master cylinder needs to be changed. Does that sound right for a leak? Any help would be appreciated but I don't think that the same shop will be doing any other further work.