Nissan Pick-ups and Pathfinder 1989-1995

Bleeding Brake System

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See Figures 1 and 2

The purpose of bleeding the brakes is to expel air trapped in the hydraulic system. The system should be bled whenever the pedal feels spongy, indicating that compressable air has entered the system. It should also be bled whenever the system has been opened or repaired. You will need a helper for this job.

In order to ease access to the bleeder screws, it may be helpful to raise the vehicle and safely support it while bleeding the brakes.

  1. Clean all the bleeder screws; since seizure is a common problem with bleeder screws, you may want to give each one a shot of a penetrating lubricant. In the event that one or more bleeder screws break off, it may be necessary to replace the attached part(s).
  2.  

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 damages 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.

  1. Fill the master cylinder with clean, unused DOT 3 brake fluid.
  2.  

Never reuse brake fluid which has been bled from the brake system.



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Fig. Fig. 1: Bleeding the front caliper-note position of the bleeder bottle and hose



Click image to see an enlarged view

Fig. Fig. 2: Bleeding the rear wheel cylinder-do not let the master cylinder run dry during the bleeding operation

  1. The sequence for bleeding is as follows:

    Models equipped with a Load Sensing Valve (LSV): LSV air bleeder, left rear wheel cylinder, right rear wheel cylinder, left front caliper, right front caliper.
     
    Models not equipped with a Load Sensing Valve (LSV): left rear wheel cylinder, right rear wheel cylinder, left front caliper, right front caliper.
     

  2.  

On models with ABS, be sure to turn the ignition OFF and detach the actuator connector. For additional information and service procedures, refer to the ABS section.



Models equipped with ABS: left rear caliper or wheel cylinder, right rear caliper or wheel cylinder, left front caliper, right front caliper, ABS actuator.
 

  1. If equipped with an LSV, attach a length of clear vinyl tubing to the LSV air bleeder. Insert the other end of the tube into a clear, clean jar half filled with brake fluid. Have your 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 your assistant slowly release the pedal. Repeat this process until no air bubbles appear in the expelled fluid.
  2.  

  1. Attach a length of clear vinyl tubing to the bleeder screw on the first caliper or wheel cylinder in the bleeding sequence. Insert the other end of the tube into a clear, clean jar half filled with brake fluid. Have your 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 your assistant slowly release the pedal. Repeat this process until no air bubbles appear in the expelled fluid.
  2.  

If the brake pedal is depressed too fast, small air bubbles will form in the brake fluid.

  1. Repeat the procedure on the other three brakes, checking the level of fluid in the cylinder reservoirs often.
  2.  

 
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