Saturn Coupes/Sedans/Wagons 1991-1998 Repair Guide

Bleeding the ABS System

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See Figures 1, 2 and 3

Prior to bleeding the rear brakes, the rear displacement cylinder pistons must be returned to the topmost or HOME position. To return the pistons to the HOME position, use a Scan tool to perform the special test, RUN ABS PISTONS UP-HOME. This test will run the pistons to the top of their travel.

  1. Fill the master cylinder with clean brake fluid and keep the reservoir at least 1 / 2 full during the bleeding operation. Install the fluid reservoir cap.
  2.  
  3. Prime the control assembly as follows:
    1. Attach a clear tube to the rear bleeder valve and submerge the tube in a transparent container of clean brake fluid.
    2.  
    3. Slowly open the valve 1 / 2 - 3 / 4 of a turn, then have an assistant depress the brake pedal.
    4.  
    5. Hold the brake pedal until fluid begins to flow from the valve, then close the valve and release the pedal.
    6.  
    7. Tighten the valve to 62 inch lbs. (7 Nm).
    8.  
    9. Repeat the procedure at the front bleeder valve.
    10.  

  4.  
  5. Once fluid flows from both control assembly valves, it may not be completely purged of air. To assure that the unit is free of air, bleed the calipers to remove air from the system' lowest points, then return and bleed the control assembly one last time.
  6.  
  7. Be sure to bleed the calipers in the proper order:
    1. Right rear
    2.  
    3. Left rear
    4.  
    5. Right front
    6.  
    7. Left front
    8.  

  8.  

If, when performing the bleeding procedure on the rear calipers, brake fluid does not come out of the bleeder, the rear displacement pistons may not be at the HOME or topmost position.

  1. Bleed each caliper, in the proper order, as follows:
    1. Attach a clear tube to the caliper bleeder valve and submerge the other end of the tube in a transparent container of clean brake fluid.
    2.  
    3. Open the valve 1 / 2 - 3 / 4 of a turn, then have an assistant slowly depress the brake pedal and hold.
    4.  
    5. Watch for air bubbles as the fluid begins to flow from the valve, then close the valve and release the pedal.
    6.  
    7. Wait 5 seconds and repeat until the pedal feels firm and no air is present in the brake line.
    8.  
    9. Tighten the valve to 97 inch lbs. (11 Nm) for the calipers and 66 inch lbs. (7.5 Nm) for the wheel cylinders.
    10.  

  2.  
  3. Bleed the control assembly from the 2 valves in the same fashion as the calipers are bled. Tighten the bleeder valves to 62 inch lbs. (7 Nm) when finished.
  4.  
  5. Check the pedal for excessive travel both with the engine OFF and with the engine running. If pedal feel is firm, proceed to Step 11.
  6.  
  7. If the pedal feel is not firm, use a Scan tool to run the ABS motor up and down 2 times, making sure the pistons are run up to the HOME position.
  8.  
  9. Start the engine and let it run for 2 seconds after the ABS light goes out, then turn the engine OFF . Repeat this ignition cycle 9 more times.
  10.  
  11. Re-bleed the entire system.
  12.  
  13. With the engine running and brake applied, check the system for leaks.
  14.  
  15. Road test the vehicle and make several normal, non-ABS stops. Then, make 1-2 ABS stops from a higher speed (about 50 mph/80 kmh).
  16.  
  17. After road testing the vehicle, it is recommended that the entire system be bled and inspected one final time.
  18.  



Click image to see an enlarged view

Fig. Fig. 1: On all Saturns, the brake fluid reservoir fill line is at the base of the fill neck



Click image to see an enlarged view

Fig. Fig. 2: Run a transparent tube from the ABS control assembly's front bleeder screw to a transparent container partially filled with clean brake fluid



Click image to see an enlarged view

Fig. Fig. 3: Attach a transparent tube to the caliper bleeder valve-rear brakes shown

 
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