Brake Bleeding: Service and Repair
Air BleedingPROCEDURE
CAUTION:
^ The FMVSS No. 116, fresh DOT3 or 4 brake fluid must be used.
^ Cover the bleeder with waste cloth when loosening it to prevent brake fluid from being splashed over surrounding parts.
^ Avoid mixing different brands of brake fluid to prevent degrading the quality of the fluid.
^ Be careful not to allow dirt or dust to get into the reservoir tank.
NOTE:
^ Start with the brakes (wheels) connected to the secondary chamber of the master cylinder.
^ The time interval between two brake pedal operations (from the time when the pedal is released to the time when it is depressed another time) shall be approximately 3 seconds.
^ The air bleeder on each brake shall be released for 1 to 2 seconds.
MASTER CYLINDER
NOTE:
^ If the master cylinder is disassembled or reservoir tank is empty, bleed the master cylinder.
^ During the bleeding operation, keep the brake reservoir tank filled with brake fluid to eliminate entry of air.
^ Brake pedal operating must be very slow.
^ For convenience and safety, two people should do the work.
1) Disconnect the brake line at primary and secondary sides.
2) Cover the master cylinder with vinyl bag.
3) Carefully depress and hold the brake pedal.
4) Close the outlet plug with your finger, and release the brake pedal.
5) Repeat the above step 3) and 4) until brake fluid is completed bled from outlet plug.
6) Remove the vinyl bag, then connect the brake pipe to master cylinder.
Tightening torque: 8 Nm (0.8 kgf-m, 5.8 ft. lbs.)
7) Using water, wash off the spilt brake fluid at the master cylinder surrounding, then wipe up the water.
8) Bleed air from the brake line.
BRAKE LINE
NOTE:
^ During the bleeding operation, keep the brake reservoir tank filled with brake fluid to eliminate entry of air.
^ Brake pedal operating must be very slow.
^ For convenience and safety, two people should do the work.
1) Make sure that there is no leak from joints and connections of the brake system.
2) Fit one end of vinyl tube into the air bleeder and put the other end into a brake fluid container.
CAUTION: Brake fluid replacement sequence; (A) Front right -> (B) Rear left -> (C) Front left -> (D) Rear right
3) Slowly depress the brake pedal and keep it depressed. Then, open the air bleeder to discharge air together with the fluid.
Release the air bleeder for 1 to 2 seconds.
Next, with the bleeder closed, slowly release the brake pedal.
Repeat these steps until there is no more air bubbles in the vinyl tube.
Allow 3 to 4 seconds between two brake pedal operations.
CAUTION: Cover the bleeder with waste cloth, when loosening it, to prevent brake fluid from being splashed over surrounding parts.
NOTE: Brake pedal operating must be very slow.
4) Tighten the air bleeder securely when no air bubbles are visible.
Air bleeder tightening torque: 8 Nm (0.8 kgf-m, 5.8 ft. lbs.)
5) Perform these steps for the brakes connecting to the secondary chamber of master cylinder, first, and then for the ones connecting to primary chamber. With all procedures completed, fully depress the brake pedal and keep it in that position for approximately 20 seconds to make sure that there is no leak evident in the entire system.
6) Check the pedal stroke.
While the engine is idling, depress the brake pedal with a 490 N (50 kgf, 110 lbs.) load and measure the distance between the brake pedal and steering wheel. With the brake pedal released, measure the distance between the pedal and steering wheel again. The difference between the two measurements must be more than specified.
Specified pedal stroke:
Without ABS 90 mm (3.54 inch)
With ABS 95 mm (3.74 inch)
When depressing brake pedal with a 490 N (50 kg, 110 lbs.) load.
7) If the distance is more than specified, there is a possibility that air is in the brake line. Bleed the brake line until pedal stroke meets the specification.
8) Operate the hydraulic control unit in the sequence control mode. (With ABS)
9) Recheck the brake stroke.
10) If the distance is more than specified, there is a possibility air is in the inside of the hydraulic unit. Repeat above steps 2) to 9) until pedal stroke meets the specification.
11) Add brake fluid to the required level (MAX. level) of reservoir tank.
12) As a final step, test run the vehicle at low speed and apply brakes relatively hard 2 to 3 times to ensure that brakes provide normal braking action on all four wheels without dragging and uneven braking.