Manual Bleeding
ABS BLEEDING PROCEDURESPrior to bleeding the brakes, the front and rear displacement cylinder pistons must be returned to the top most position. Using a TECH 1 or T-100 (CAMS), enter the manual control function and "apply" the front and rear motors. Be sure the enable relay is "ON."
If a TECH 1 or T-1OO are not available, bleed the front brakes. Start engine and allow it to run for at least 10 seconds, (with foot off brake) this will cause the ABS to initialize itself. This will return the front and rear displacement cylinders to the top position. The entire brake system should now be rebled.
CAUTION: Use ONLY DOT 3 brake fluid from a clean, sealed container. Do NOT use fluid from an open container that may be contaminated with water. Do NOT use DOT 5 brake fluid.
(Figure 1) Bleeding Brakes:
MANUAL BLEEDING
In the following steps, use a suitable container and/or shop cloths to catch fluid and prevent it from contacting any painted surfaces. Follow ALL the steps below to complete system bleeding.
1. Clean reservoir cover and surrounding area.
2. Remove reservoir cover and inspect fluid level. Fill to the correct level if necessary and then reinstall reservoir cover.
3. Prime ABS hydraulic modulator and master cylinder assembly.
4. Attach bleeder hose to rearward bleeder valve and submerge opposite hose end in clean container partially filled with brake fluid.
5. Open rearward bleeder valve 1/2 to 3/4 turns and depress brake pedal until fluid begins to flow. Close valve and release brake pedal. Repeat until no air bubbles are present.
6. Repeat procedure for forward bleeder valve until fluids begins to flow.
NOTE: Once fluid is seen to flow from both modulator bleeder valves, the ABS hydraulic modulator and master cylinder assembly is sufficiently full of fluid. However, it may not be completely purged of air. At this point move to the wheel brakes and bleed them. This ensures that the lowest points in the system are completely free of air and THEN the ABS hydraulic modulator and master cylinder assembly can be purged of any remaining air.
7. Remove reservoir cover and inspect fluid level. Fill to the correct level if necessary and then reinstall reservoir cover.
8. Raise vehicle and suitably support.
NOTES:
^ Bleed wheel brakes in sequence shown below:
a. Right rear.
b. Left rear.
c. Right front.
d. Left front.
^ To assist in freeing entrapped air from calipers, tap LIGHTLY on caliper castings with a rubber mallet.
9. Attach bleeder hose to right rear bleeder valve and submerge opposite hose end in clean container partially filled with brake fluid.
10. Open bleeder valve and slowly depress brake pedal. Close valve and slowly release brake pedal. Wait 5 seconds.
11. Repeat step 10 until brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
12. Repeat steps 9, 10 and 11 on the left rear wheel brake and then on the front wheel brakes.
13. Lower vehicle, then check fluid level in reservoir and fill to the correct level, if necessary, using clean brake fluid.
14. Install reservoir cover and diaphragm assembly.
15. Attach bleeder hose to rearward bleeder valve of the hydraulic modulator and master/cylinder assembly and submerge opposite in clean container partially filled with brake fluid.
16. Depress brake pedal with moderate force, then slowly open rearward bleeder valve 1/2 to 3/4 turns and allow fluid to flow.
17. Close valve and release brake pedal. Wait five seconds.
18. Repeat above steps, including the five second wait, until all the air is purged from the system.
19. Repeat procedure for forward bleeder valve.
20. Check fluid level in reservoir and fill to the correct level, if necessary, using clean brake fluid.
Inspect
With ignition "ON," apply brake pedal with moderate force and hold. Note pedal travel and feel.
^ If pedal feels firm and constant and pedal travel is not excessive, start the engine. With the engine running, re-check the pedal travel. If it's still firm and constant and pedal travel is not excessive, go to step 21.
^ If pedal feels soft or has excessive travel either initially or after engine start. Use the TECH 1, "Release" then "Apply" the motors 2 to 3 times and cycle the solenoids 5 to 10 times. Now repeat bleeding procedure.
21. Road test the vehicle. Make several normal (non ABS) stops from a moderate speed to ensure proper brake system function.