Nissan 240SX/Altima 1993-1998 Repair Guide

Bleeding the Brake System

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See Figures 1, 2 and 3



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Fig. Fig. 1: The brake system can be bled using a vacuum type bleeder



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Fig. Fig. 2: Bleed the brakes using a clear plastic container and tubing. When all bubbles disappear, the brakes are bled



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Fig. Fig. 3: Loosen the bleeder screw using a line wrench. This will prevent the fitting from rounding off


WARNING
Clean, high quality brake fluid is essential to the safe and proper operation of the brake system. You should always buy the highest quality brake fluid that is available. If the brake fluid becomes contaminated, drain and flush the system, then refill the master cylinder with new fluid. Never reuse any brake fluid. Any brake fluid that is removed from the system should be discarded.

When any part of the hydraulic system has been disconnected for repair or replacement, air may get into the lines and cause a spongy pedal action (because air can be compressed and brake fluid cannot). To correct this condition, it is necessary to bleed the hydraulic system to be sure all air is purged.

When bleeding the brake system, bleed one component at a time, beginning at the one with the longest hydraulic line (farthest from the master cylinder). ALWAYS keep the master cylinder reservoir filled with fresh brake fluid during the bleeding operation. Never use brake fluid that has been drained from the hydraulic system, no matter how clean it is.

  1. Clean all dirt from around the master cylinder fill cap, remove the cap and fill the master cylinder with brake fluid until the level is within 1 / 4 in. (6mm) of the top edge of the reservoir.
  2.  
  3. Clean the bleeder screws. The bleeder screws are located on the back of the brake backing plate (drum brakes) and on the top of the brake calipers (disc brakes). Some master cylinders and other brake components such as ABS modulators have bleeders located on them also.
  4.  
  5. Attach a length of rubber hose over the bleeder screw and place the other end of the hose in a glass jar, submerged in brake fluid.
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  7. Open the bleeder screw 1 / 2 - 3 / 4 turn. Have an assistant slowly depress the brake pedal.
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  9. Close the bleeder screw and tell your assistant to allow the brake pedal to return slowly. Continue this process to purge all air from the system.
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  11. When bubbles cease to appear at the end of the bleeder hose, close the bleeder screw and remove the hose. Tighten the bleeder screw to 61-87 inch lbs.(7-9 Nm).
  12.  
  13. Check the master cylinder fluid level and add fluid accordingly. Do this after bleeding each component.
  14.  
  15. Repeat the bleeding operation at the remaining components, ending with the one closet to the master cylinder.
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  17. Fill the master cylinder reservoir to the proper level.
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