This requires a properly sized box wrench for the bleeder screws and a clear plastic hose connected to a clear plastic container (a clean soda bottle works good). New brake fluid is also a must. Start by topping off the master cylinder with fresh fluid and pouring about 1-inch of fluid into your clear container. At the caliper farthest from the master cylinder attach one end of the clear plastic hose to the bleeder screw and run the other end of the plastic hose into the fresh brake fluid in your container. Open the bleeder screw and have your helper VERY SLOWLY push the brake pedal by hand until fluid comes out and then close the bleeder. Next, have your partner very slowly push the pedal again with modest pressure ONE TIME ONLY until hydraulic resistance is encountered. Ask your partner to hold at this point and notify you by saying that he is "holding." Open the bleeder using the same modest pressure, letting the pedal go to the floor or as far as it can until it stops, close the bleeder, notify your partner by saying, "sealed."
Repeat this bleeding sequence until all signs of air are purged (no bubbles) from the fluid. To avoid aerating the fluid, never stroke the pedal more than once and don't let the master cylinder run dry. Be sure to check fluid level often. Finally, carefully tap on the caliper with a block of wood or plastic hammer to dislodge any air bubbles that may be trapped and repeat the bleeding sequence once more.
Move to the wheel that is the next farthest from the master cylinder and repeat the procedure. Any time you open the brake system, it is advisable to repeat the bleeding process after driving the vehicle for a day, as driving may dislodge some additional air bubbles.
Note: Flushing your brake fluid yearly is a good practice to get into. Moisture is the number one killer of brake fluid, silicone fluids excepted (but the experts we spoke to agree that you should avoid that stuff like the plague). Open your master cylinder and look at the fluid. If it's black and murky, it's way past the time for a flush.
Whose Valve Is It Anyway?
When discussing brake systems, you'll often hear discussion of valves. But these are not of the intake and exhaust variety.
The techs at Master Power offered several brake valve definitions, which you should familiarize yourself with to better understand brake functions.
It is installed in-line to limit pressure to the rear brakes and control rear wheel lock up under heavy braking. Full pressure is always available to the front brakes when a proportioning valve is correctly installed. Most stock cars come with a non-adjustable proportioning valve, but replacing it with an adjustable proportioning valve can improve the braking of ANY car, regardless of what kind of brakes it has.
Metering ValveUsed on front disc/rear drum cars to better balance the front-to-rear brakes. A metering valve does not allow the front brake pressure to rise until the pressure at the rear drums has risen sufficiently to overcome the brake shoe return springs.
Residual Pressure Valve
A 10-pound valve installed in the master cylinder to maintain line pressure in rear drum brakes and keep the shoes close to the drums giving a higher, firmer pedal. A 2-pound valve is required inline to either the front or rear brakes whenever the master cylinder is mounted lower than the calipers. It prevents fluid backflow into the master cylinder.
A combination valve incorporates metering, proportioning, and a 10-pound residual into one valve. These are used on many OEM disc/drum systems.