Document VGbDVj1o8zoRRzrDjG7Ea7zm4

LESSON ONE-MODULE 2 BRAKE SYSTEM SERVICE BRAKE SYSTEM BLEEDING (continued) Whenever bleeding an entire brake system, the usual method is to begin by bleeding the master cylinder (if equipped with a bleeder valve). If the master cylinder does not have a bleeder valve, the line fittings can be used instead. Then bleed the wheel cylinder farthest from the master cylinder. Continue by bleeding each wheel cylin der from the farthest to the closest in the sequence. This procedure may vary with the type of system you are working with. Always refer to the service manual for the procedures that apply to the specific vehicle you are working on. The following are descriptions of various brake bleeding techniques. A CAUTION: Brake Fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water. NOTE: Regardless of the method of bleeding that is used, a bleeder hose and jar should always be used. One end of the hose is pushed over the end of the bleeder valve, and the other end of the hose is submerged in brake fluid in the jar. This prevents spillage and allows you to visually check for air bubbles forced out of the brake system. Manual Bleeding Manual bleeding requires no special equipment, but it does require two people to perform it. One person pumps the brake pedal slowly and firmly, to force fluid through the system. After four or five applications of the brake pedal, the pedal is held down. At that time the second person opens the bleeder valve at the wheel cylinder, allowing the fluid and air in the line to escape. The pedal sinks to the floor as the fluid and air escapes. The pedal must not be released until the bleeder valve is closed, or air will be drawn into the system. Repeat this procedure until air bubbles are no longer evident at that wheel cylinder. Check the fluid level in the master cylinder frequently. If the fluid level in the master cylinder becomes too low, air could be drawn into the hydraulic system. 66 September, 2005 Brake System Diagnosis and Repair