Pressure Bleed Procedure

The 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, oil, and other contaminants from entering the hydraulic system.

IMPORTANT:
You can expect to use two quarts of brake fluid to thoroughly bleed the system.





1. Begin by attaching the pressure bleeder adaptor J29567 to the master cylinder (figure 1).
2. Fill the pressure bleeder tank J29532 at least 2/3 full with Delco Supreme No. 11 Hydraulic Brake Fluid (GM P/ N 1052535) or an equivalent DOT 3 motor vehicle brake fluid. The bleeder tank must be bled each time brake fluid is added.
3. Charge the bleeder tank to 140-170 kPa (20-25 psi) and connect the hose from the bleeder tank to the bleeder adaptor.





4. Open the internal bleed screws 1/4 to 1/2 turn, on each side of the BPMV (figure 2).








5. Attach the valve pressure bleeding tools J39177 to the left and right high pressure accumulator bleed valve stems of the BPMV (figure 3) and to the combination valve (figure 4). Tighten tool J39177 only finger tight.
6. Open the pressure bleeder tank valve.
7. Bleed each wheel in the following sequence:
- Right rear
- Left rear
- Right front
- Left front
NOTE:
Rear wheel bleeder valves are 5/16 in. (8 mm) and front wheel bleeder valves are 10 mm.
NOTE:
A clear plastic hose can be attached to the bleeder valve and immersed into a container partially filled with clean brake fluid.
8. Open the bleeder valve at least 3/4 of a turn and allow the fluid to flow until no air is seen in the fluid. Tighten the bleeder valve.
9. Repeat step 7 and 8 at each wheel cylinder/caliper until all the air is purged.
10. Disconnect the bleeder tank hose from the bleeder adaptor and remove the bleeder adaptor.
11. Fill the master cylinder to the proper level and replace lid.
12. CLOSE and tighten the two BPMV internal bleed screws (Figure 2) to 7 N-m (60 lbs.in.).
13. Remove the valve pressure bleeding tools J39177 from the BPMV high pressure accumulator bleed valve stems and the combination valve.
14. With the ignition switch "ON" and the engine off, bleed the pump and pressure (lower) portion of the BPMV by performing six ABS function tests with the Tech-1.

IMPORTANT:
DURING THE TECH-1 FUNCTION TESTS, THE BRAKE PEDAL MUST BE FIRMLY DEPRESSED. THIS WILL PUSH ANY AIR FROM THE CONTROL AREA OF THE BPMV INTO THE BRAKE SYSTEM.

15. Finally, rebleed the four wheel cylinder/calipers again, to purge any remaining air put into the system during the function tests. Use either the pressure bleed or manual bleed for this step.

IMPORTANT:
DO NOT OPEN THE BPMV INTERNAL BLEED SCREWS OR DEPRESS THE HIGH PRESSURE ACCUMULATOR BLEED VALVES WHEN REBLEEDING AFTER THE FUNCTION TESTS.

16. Tighten all four wheel cylinder/caliper bleeder valves to 7 N-m (60 lbs.in.).
17. Remove the bleeder adaptor, if using the pressure bleed procedure (figure 1), and fill the master cylinder to the proper level with brake fluid.
18. Apply firm pressure to the brake pedal and evaluate the brake pedal feel.

IMPORTANT:
MAKE SURE YOU HAVE A GOOD, HARD BRAKE PEDAL BEFORE ATTEMPTING TO MOVE THE VEHICLE.

19. Repeat the entire brake bleed procedure if necessary.