I'm putting in a new Master Cylinder, and was wondering if I have to bench bleed it or not. Anyone know how I have to do this before I take it out?

 

Yes. I Did this for my truck, but it is the same for all brakes. I installed the master cylinder to the brake booster. Then, I screwed hose nipples to the ports that normally bolt up to the brake lines. Next I put small clear hoses on them until they looped around into the fluid resivoir. I filled the master cylinder with fluid and began pumping slowly. It took me over an hour to get all the air out. Then you hook up the brake lines to the master cylinder. leave them just cracked loose. Have an assistant press the brake pedal slowly and tell you before they bottom out the pedal. When they tell you, tighten the fittings. have them release the pedal and then push on it. Crack the fittings loose again and repeat these last few steps until no air comes out.