Antilock Brake System Bleeding Procedures

GENERAL INFORMATION
The hydraulic system for the base brakes must be bled anytime air enters the hydraulic system. Air can enter the hydraulic system for the base brakes due to the disconnection of brake lines, hoses or any other hydraulically operated component of the base brake system. The ABS system, particularly the Integrated Control Unit (ICU), should only be bled when the ICU is replaced or it is removed from the vehicle. The ICU must also always be bled if for any reason it is suspected that the ICU has ingested air. Under most circumstances that require the bleeding of the brakes hydraulic system, only the base brake hydraulic system needs to be bled.

It is important to note that excessive air in the brake system will cause a soft or spongy feeling brake pedal.

During the brake bleeding procedure, be sure the brake fluid level remains close to the FULL level in the master cylinder fluid reservoir. Check the fluid level periodically during the bleeding procedure and add DOT 3 brake fluid as required.

The ITT Teves Mark 20 ABS must be bled as two independent braking systems. The non ABS portion of the brake system is to be bled the same as any non ABS system. This brake system can be either pressure bled or manually bled.

The ABS portion of the brake system MUST be bled separately. This bleeding procedure requires the use of the DRB Diagnostic Tester and the bleeding sequence procedure outlined below.

ABS BLEEDING PROCEDURE
When bleeding the ABS system, the following bleeding sequence MUST be followed to insure complete and adequate bleeding. The ABS system can be bled using a manual bleeding procedure or standard pressure bleeding equipment.

If the brake system is to be bled using pressurized bleeding equipment, refer to Bleeding Base Brakes.
1. Assemble and install all brake system components on the vehicle making sure all hydraulic fluid lines are installed and properly torqued.
2. Connect the DRB Diagnostics Tester to the diagnostics connector. The Teves Mark 20 ABS diagnostic connector is located under the instrument panel to the left of the steering column cover.
3. Using the DRB, check to make sure the Controller Antilock Brake (CAB) does not have any fault codes stored. If it does, remove them using the DRB.

WARNING: When bleeding the brake system wear safety glasses. A clear bleed tube must be attached to the bleeder screws and submerged in a clear container filled part way with clean brake fluid. Direct the flow of brake fluid away from the painted surfaces of the vehicle. Brake fluid at high pressure may come out of the bleeder screws when opened.

4. Bleed the base brake system using the standard pressure or manual bleeding procedure.
5. Using the DRB, go to the "Bleed ABS" routine. Apply the brake pedal firmly and initiate the "Bleed ABS" cycle one time. Release the brake pedal.
6. Bleed the base brake system again, as in step Step 4 above.
7. Repeat steps Step 5 and Step 6 above until brake fluid flows clear and is free of any air bubbles. Check brake fluid level in reservoir periodically to prevent reservoir from running low on brake fluid.
8. Test drive the vehicle to be sure brakes are operating correctly and that the brake pedal does not feel spongy.