How to Bleed the Brakes on 1990 Mazda Truck

The 1990 Mazda truck has a diagonal braking system, which means that the left front and the right rear brakes are fed from the same line; and the right front and left rear also share the same line. This design eliminates the chance of losing the front or rear brakes in the event of a line failure, representing a good safety feature. This way, you always have an operational front and rear brake, and being on opposing sides, the truck will not pull to one side or the other. In 1978, the automated braking system was introduced to the Mazda truck, marking the beginning of high-tech braking systems. The ABS system prevents the tires from locking up and causing a skid or spin, and decreases the stopping distance dramatically. Bleeding the brakes on a 1990 Mazda truck without special equipment requires a helper to pump the brakes; it entails bleeding the rear brake furthest from the master-cylinder and proceeding diagonally to the opposite side in the front.

Instructions

1

Raise the truck with the floor jack and place the jack stands under the frame. Lower the truck to rest on the stands. Explain to the helper that when told to do so, he must press the brake pedal to the floor, but under no circumstance allow the pedal up until told to do so. If the pedal is allowed to rise while the brake bleeder is open, it will suck air into the wheel cylinder or brake caliper, which makes it very difficult to bleed of air. This causes a spongy brake pedal.

2

Open the hood and remove the cap on the master cylinder reservoir, located on the driver's side firewall. Fill the reservoir, if needed, to the "Full" mark. Replace the cap.

3

Open the bleeder screw on the top-rear of the brake backing plate, on the right-rear wheel, using a socket. Tell the helper to push the pedal to the floor and hold it there.

4

Close the bleeder screw just enough to be snug, and tell the helper to release the pedal. Have the helper pump the brake pedal two times and then leave the pedal up.

5

Open the bleeder, and have the helper repeat depressing the pedal and holding it down. Close the bleeder and allow him to release the pedal again. Continue this procedure until all the air is removed and a solid stream of brake fluid is seen emerging from the bleeder.

6

Check the fluid level in the master cylinder reservoir and correct, as necessary. Move to the left front brake caliper and repeat the procedure. The bleeder on the caliper is on the top-inside and is easy to see. The left-rear brake will be next, followed by the right-front one. Always check the level in the master cylinder before proceeding to the next brake. Lift the truck and remove the jack stands, then lower the truck to the ground.