Q&A

 Master

The job takes a mechanic around 1-2 hours and they will bleed the brake system too. If you are going to do this, get a good repair manual and read up on what needs to be done and what tools you'll need. Look at the location of the master cylinder and see what it will take to access the bolts to remove it and the brake lines too, they can be tough to access.
You might find a free manual here: http://bit.ly/autozone_repair_info or go to http://bit.ly/alldata_repair_manuals or http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.