See Figures 1 and 2
The purpose of bleeding the brakes is to expel air trapped in the hydraulic system. The system must be bled whenever the pedal feels spongy, indicating that compressible air has entered the system. It must also be bled whenever the system has been opened or repaired. You will need a helper for this job.
The sequence for bleeding is as follows:
1970-71: Right rear, left rear, right front, left front;
It is not necessary to run the engine on 1972-79 models with a vacuum booster.
- Clean all the bleeder screws. You may want to give each one a shot of a penetrating lubricant to loosen it up; seizure is a common problem with bleeder screw, which then break off, sometimes requiring replacement of the part to which they are attached.
- Fill the master cylinder with DOT 3 brake fluid.
Brake fluid picks up moisture from the air. Don't leave the master cylinder or the fluid container uncovered any longer than necessary. Be careful! Brake fluid eats paint.Check the level of the fluid often when bleeding, and refill the reservoirs as necessary. Don't let them run dry, or you will have to repeat the process.
- Attach a length of clear vinyl tubing to the bleeder screw on the wheel cylinder (or master cylinder). Insert the other end of the tube into a clear, clean jar half filled with brake fluid.
- Have you helper slowly depress the brake pedal. As this is done, open the bleeder screw 1 / 3 - 1 / 2 of a turn, and allow the fluid to run through the tube. Then close the bleeder screw before the pedal reaches the end of its travel. Have you assistant slowly release the pedal. Repeat this process until no air bubbles appear in the expelled fluid.
If the brake pedal is depressed too fast, small air bubbles will form in the brake fluid.
- Repeat the procedure on the other three brakes, checking the level of fluid in the cylinder reservoirs often.