Drum brakes call springs moreover to hydraulic pistons to activate the brake.
Brake problems on any vehicle poses a large safety puzzle. When brakes carry air trapped in the path, the brakes fail to properly engage, thus diminishing your stopping aptitude. Whether no fluid is in the column, you lose all stopping potentiality. The One thousand nine hundred ninety one Chevrolet Motor lorry series uses a skilled cylinder and brake booster to provide further gift to the brakes. Bleeding the brakes frees trapped air from the wrinkle. Sometimes long amounts of air are trapped, forming it come forth as though no fluid is in the wrinkle.
Instructions
1. Lift the rear of the vehicle one rotate at a era. Deposit jack stands under Everyone revolve at the axle as you stand the rotate. Remove the lug nuts with a lug wrench and remove the tires. City them to the side.
2. Visually see the brake lines future from both rear brakes. Hint these back to the engine while looking for signs of leaks or breaks in the wrinkle. Conceive certain to test the drums and for signs of leaks. You Testament entail to carefully pull off the drum and gaze the caliper for signs of leaking. You should examine no signs of fluid within the drum cylinder. Change the drum onto the drum cylinder. Whether no breaks in the limit or leaks are identified, remove the top off of the brake fluid reservoir and fill to the entire border.
3. Loosen the bleed screw on the passenger rear tire ahead. When bleeding brakes, always countdown from the brake farthest from the reservoir to accomplish confident trapped air does not leak back into the manner. Deposit the rubber tubing onto the bleed screw and into the clarion plastic bottle. Produce firm the bottle has a inconsequential proportions of brake fluid in the backside and the edge of the rubber tubing is immersed in the fluid.
4. Proof for vacuum compel on the border. Admit an assistant depress the brake pedal and dominion it in area. Loosen the bleed screw fully so that the air can escape. Once complete, install the wheels and lower the vehicle to the ground. Test the brakes.
5. Close the bleed screw and build up pressure in the brake lines. Have your assistant firmly press the brake pedal down three to five times. On the last time, have him hold it down while you loosen the bleed screw. If no air was coming out previously and no vacuum was identified, you have a clogged bleed screw. Increasing the pressure in this manner will force any blockage out. Make sure you have vacuum in the line after clearing out obstructions by repeating step four.
6. Bleed the passenger rear tire. Have the assistant press the brake pedal to the floor and hold it there. Loosen the screw and allow the air to escape. Once the bubbles stop, tighten the screw and have the assistant release the pedal. Repeat the process until no air is coming out of the line. Tighten the bleed screw firmly. The process may take an extensive amount of time if a lot of air is present. Monitor the fluid reservoir and refill it as necessary. Do not let the reservoir get less than half full.
7. Bleed the remaining brakes (repeat step 6) starting with the driver rear, then the passenger front and then the driver front. When you have completed the rear tires, replace the wheels and lug nuts and lower them to the ground. Raise the front wheels and remove those wheels in the same fashion. You should see bubbles come out the end of the tubing. Have the assistant release the brake pedal. If a vacuum exists, which is necessary for proper operation, the tubing will suck fluid out of the bottle. If that is the case, then you just have extensive amounts of air trapped in the line.
