The brake system bleeding is the fluid pressure to force air out of the brake line connections from wheel cylinder bleeding screws. There are two methods of bleeding brakes.
1. Manual Bleeding
2. Pressure Bleeding 1. Manual Bleeding Manual bleeding uses master cylinder pressure to force fluid and trapped air out of the system. Basically attach one end of a hose to a bleeder screw. Place the other end in a jar partially filled with brake fluid. During this process another mechanic apply light foot pressure on the brake pedal. Open the bleeder screw or fitting while watching for air bubbles at the hose.
Close the bleeder screw or titling and tell your helper to release the pedal. Repeat this procedure until no air bubbles come out the hose. Perform operation on the other wheel cylinders or a brake line connections, if needed. Typically, start bleeding a the wheel cylinder for theist from the master cylinder. Source brake systems require special procedure when bleeding. For detail procedure, check cars service manual. Check manufactures instruction. 2. Pressure Bleeding of a Brake System It is done by using air pressure trapped inside a metal air tank pressure bleeding is quick and easy because you do not need a helper to work on the brake pedal.
A special adopter s installed over the master cylinder reservoir. A pressure hose connects the master cylinder and pressure tank. A valve in the hose controls the flow.
Note: Check manufacture instructions. You may need to push or pull out the metering valve stem before bleeding the brake system.
Pure enough brake fluid in the bleeder tank to reach the prescribed level. Charge the tank with 10 to 15 psi (69 to 103 kPa)of air pressure. Fill the master cylinder with the brake fluid. Install the adopter and hose on the master cylinder. Open the valve in the hose. You are now ready to bleed the brakes. Open act bleeder screw or fitting until all fluid becomes clear, close the screw or fitting. Repeat bleeding operation on the other wheel cylinders in proper order.
Note: A special pressure bleeding adopter is needed on master cylinders using a “plastic reservoir”. Use an adopter that seals over the ports in the bottom on the master cylinder. This will avoid possible reserved damage. A special vacuum or suction bleeder, mounted at each wheel bleeder screw, will also work.