7. BLEEDING OF HYDRAULIC SYSTEM The process of removing air from the hydraulic pipelines and cylinder is known as “Bleeding”. The brake hydraulic lines are based on diagonal split system. Whenever any brake line or hose is disconnected at the wheel, bleeding operation must be performed at both the ends of the line of the removed pipe or hose. (I.e. if the rear left side brake pipe or hose is disconnected, both the rear left and front right side of the system is to be bleeded). When any joint part of the Master cylinder, other joint part between the master cylinder and each brake of the wheel is removed or the level of brake fluid in the reservoir has been allowed to fall so low that the air has been drawn into the system, then the hydraulic brake system must be bleed at all 4 wheel brakes. As the hydraulic lines of brake system are of DIAGONAL SPLIT, always perform bleeding operation starting with the caliper farthest from master cylinder and then at the front brake assembly of the same brake circuit. Repeat the same on the other brake circuit also. Brake fluid may cause damage to paint. So make sure that brake fluid should not touch the painted surface, if it accidentally touches the painted surface, wipe immediately and clean the surface. D. IVBAC BLEEDING PROCEDURE A normal bleeding procedure can be employed whenever: Replacing caliper or Drum Brakes. • Replacing of brake hoses. • Any hydraulic connection is loosened for any • purpose. Spongy / Soft brake pedal or pedal travel high • complaint. Carefully clean all dirt from around the reservoir filler cap. Before commencing bleeding, at each bleed screw, remove the dust cap and clean thoroughly. Attach transparent (vinyl) bleed tube to the bleeder screw top of the Rear Left Caliper and insert the other end into a clean glass container containing recommended brake fluid to submerge the end of the tube. Bleed screw must be closed at the end of each Bleed cycle on individual wheel. Ensure that Vehicle Battery is connected and • the 46 pin IVBAC connector is connected to the IVBAC system. Turn on the vehicle ignition to “READY” state. • Initiate diagnosis. • Using the Tata Diagnostic Tool ensure that • “Assembly Mode” is activated in the IVBAC ECU by going to “WRITE” section. Base brake bleeding • 1. Put on the brake bleeding device on the reservoir and adjust 2 bar over pressure. The Reservoir should be filled with caution so that over filling which causes spillage outside of the Reservoir and into the vehicle engine compartment is avoided. 2. Execute base brake bleeding starting from rear left wheels by pressing the brake pedal periodically throughout the full stroke of the pedal and then holding it depressed, loosen bleeder plug about one-third to one-half turn. This is sufficient to allow the brake fluid to flow freely. 3. There should be an interval of 3 to 4 seconds before making the next stroke. This action should be repeated until bubbles of air cease to appear at the end of the bleed tube NOTE Use only DOT4 brake fluids confirming to SAE J1704 from a sealed container. Ensure brake fluid is not contaminated. NOTE Bleed screw must be closed at the end of each Bleed cycle on individual wheel. BRAKES 35
RkJQdWJsaXNoZXIy MTIwNTUz