Pressure Bleeding
Note: Use only Supreme II (GM 1052542) or equivalent DOT 3 brake fluid from a clean, sealed container. Do not use fluid from an open container that may be contaminated with water. The use of DOT 5 (silicone) brake fluid is not recommended. Reduced braking performance or durability may result.
Note: Avoid spilling brake fluid on any of the vehicle's painted surfaces, wiring, cables or electrical connectors. Brake fluid will damage paint and electrical connections. If any fluid is spilled on the vehicle, flush the area with water to lessen the damage.
Note: Pressure bleeding equipment must be of the diaphragm type. It must have a rubber diaphragm between the air supply and the brake fluid to prevent air, moisture and other contaminants from entering the hydraulic system.
1. Clean Fluid reservoir cover and surrounding area.
2. Remove fluid reservoir cover.
3. Inspect fluid to be at proper level. Add clean brake fluid as required.
4. Connect bleeder adaptor J 35589 to brake fluid reservoir.
5. Connect bleeder adaptor to pressure bleeding equipment.
6. Adjust pressure bleed equipment to 35-70 kPa (5-10 psi) and wait for approximately 30 seconds to ensure there is no leakage.
7. Pressure bleed equipment to 205-240 kPa (30-35 psi).
8. Proceed to bleed the hydraulic modulator as follows with pressure bleeding equipment connected and pressurized:
A. Attach a clear plastic bleeder hose to the rearward bleeder valve on the hydraulic modulator. Submerge opposite hose end in a clean container partially filled with clean brake fluid.
B. Slowly open bleeder valve and allow fluid to flow until no air is seen in fluid.
C. Close valve when fluid flows without any air bubbles.
D. Repeat Steps 8B and 8C until no air bubbles are present.
E. Tighten hydraulic modulator bleeder valve to 9 Nm (80 lb.in.).
F. Relocate the bleeder hose to the hydraulic modulator forward bleeder valve and repeat Steps 8A through 8D.
Brake Pipe Connections:
9. Proceed to bleed the hydraulic modulator brake pipe connections as follows with pressure bleeding equipment connected and pressurized:
Important: Use a shop cloth to catch escaping brake fluid. Take care to prevent fluid from running down motor pack and entering the motor pack base or into the electrical connector. Also, do not allow brake fluid to contact any painted surfaces as surface damage will occur. If brake fluid does contact any surface, flush surface with water to lessen damage.
A. Crack (slightly open) the forward brake pipe tube nut on the master cylinder and check for air in escaping fluid.
B. When air flow ceases, immediately tighten tube nut.
C. Tighten brake pipe tube nut to 32 Nm (24 lb.ft.).
D. Repeat Steps 9A and 9B for remaining three brake pipe connections, moving from front to rear.
11. Raise vehicle and suitably support. Proceed as follows to bleed wheel brakes in sequence.
Important: Bleed sequence:
Right rear.
Left rear.
Right front.
Left front.
A. Attach bleeder hose to bleeder valve and submerge opposite hose end in a clean container partially filled with clean brake fluid.
B. Slowly open bleeder valve and allow fluid to flow.
C. Close valve when fluid begins to flow without any air bubbles. Tap lightly on the adapter with a rubber mallet to dislodge any trapped air bubbles.
12. Repeat above sequence on left rear wheel brake.
13. Repeat above sequence on front wheel brakes.
14. Lower vehicle.
15. Remove bleeder adapter J35589.
16. Inspect fluid level in reservoir and fill to proper level if necessary.
17. Install fluid reservoir cap.
18. With ignition "ON," apply brake pedal with moderate force and hold. Note pedal travel and feel. If pedal feels soft or has excessive travel either initially or after engine start, perform the following:
With a Tech 1, "Release" then "Apply" each motor 2 to 3 times and cycle each solenoid 5 to 10 times. When finished, be sure to "Apply" the front and rear motors to ensure the pistons are in the upmost position. DO NOT DRIVE THE VEHICLE. If a Tech 1 is not available, remove foot from brake pedal, start the engine and allow it to run for at least 10 seconds to initialize the ABS; DO NOT DRIVE THE VEHICLE. After 10 seconds, turn the ignition "OFF". This initialization procedure MUST be repeated 5 times to ensure any trapped air has been dislodged. Now repeat bleeding procedure starting at Step 1.
19. Road test the vehicle. Make several normal (non ABS) stops from a moderate speed to ensure proper brake system function. Allow adequate cooling time between stops.