Actually the master cylinder I replaced last year for some odd reason it kept going out bit finally it stop leaking! So its good. I do have to fix my emergency brakes though I completely hate the rear brakes on my truck !
I have heard about people on here using oven cleaner. But, I found this stuff at the dollar store, and in my opinion it works as good as the Westley's Bleach-White that i was using before. You can't go wrong for $1. I would also use a pressure washer if possible. Only once everything was absolutely clean would I even consider any painting.