Before installing MC, "bench bleed" the MC. To do that, take two small sections of brake tubing (with flare nuts and flared ends) and screw them into the MC ports. Have the tubing bent around so the end of the tubes aims back into the MC reservoir opening.
Mount the MC in a bench vise (or clamp upright securely in some manner to a solid surface), and fill reservoir with brake fluid. Pump end of MC repeatedly until lines returning to reservoir are free of air bubbles.
Now mount MC on vehicle, and connect the appropriate hard lines to the ports on the MC. Keep the MC FULL OF FLUID after bench bleeding and while mounting/connecting.
The next step is to "gravity bleed" the system. To do this, connect a piece of tubing (clear fishtank air tubing works well) to all four bleeder screws, and put the end of the tube into a suitable receptacle to catch the old brake fluid. Plastic soft drink bottles work real well. Loosen all the bleeder fittings about 1-2 turns to allow old brake fluid to run down the clear tubing, and be SURE keep the MC reservoir full. (If it runs dry, you have to START ALL OVER.)
After about 15-20 minutes (or when the fluid coming out all the hoses is CLEAR, like new brake fluid), close all four bleeder fittings.
Now it's time to "pressure bleed" the system. You will need a helper for this, someone who can pump the brake pedal as necessary. The pressure bleeding must be done on each wheel individually, in the following SPECIFIC ORDER: R. Rear, L. rear, R. front, L. front.
At each wheel, here is what is done:
1. top off the MC reservoir
2. have assistant place foot on brake pedal
3. loosen bleeder screw (while clear tube is still attached)
4. have assistant press brake pedal. It will go all the way to the floor, forcing old brake fluid out bleeder screw and thru tubing.
5. once pedal is down fully, snug bleeder screw (this is important)
6. have assistant release brake pedal to full up position
7. repeat steps 3 thru 6 as necessary until NO air bubbles are visible in clear tubing.
8. be sure to periodically check MC reservoir, and DO NOT let it run out of brake fluid. If it goes dry, you start ALL OVER.
Repeat this at all four wheels. When done, tighten all bleeder screws, remove bleeder tubing, top off MC reservoir, and replace cap on reservoir.
Note: brake fluid will harm most painted surfaces. Be sure to wash any spilled brake fluid off with water.