Document gLmeezXzwnMB5KKQ33G9d8v3

BRAKE SYSTEM SERVICE Pressure Bleeding LESSON ONE-MODULE 2 Pressure bleeding requires the use of a Rotunda Pressure Brake Bleeder. Use of a pressure bleeder allows brake bleeding to be performed efficiently by a single technician. A pressure bleeder usually consists of a tank which is divided into two chambers by a flexible diaphragm. One chamber contains brake fluid, the other contains air. The air chamber can be pressurized with compressed air from the shop air system. When the air chamber is pressurized, it exerts pressure through the flexible diaphragm against the brake fluid in the fluid chamber. A valve in the fluid side of the tank allows fluid to escape through a hose to an adapter. This adapter fits tightly over the master cylinder reservoir, thus allowing the fluid to enter the brake system under pressure. In this way the pressure bleeder not only pressurizes the brake system, it also maintains the fluid level in the master cylinder. The bleeder tank must contain enough brake fluid to complete the bleeding operation and should be charged to 69207 kPa (10-30 psi). Never exceed 345 kPa (50 psi). Follow the instructions that come with the brake bleeder machine. Gravity Bleeding Gravity bleeding basically consists of letting the brake fluid's own weight force it through the system. This is accomplished by simply opening wheel cylinder bleeder valves one at a time, until a solid flow of fluid flows out of the valve. Be sure to check the master cylinder fluid level often to prevent it from running dry. Brake System Diagnosis and Repair September, 2005 67