Manual Bleeding
PROCEDURE1. Make sure vehicle ignition is off
2. Depressurize Powermaster III Unit, refer to Antilock Brake System / Service and Repair.
3. Clean and remove reservoir cover and diaphragm assembly.
4. Fill reservoir with DOT 3 brake fluid to the correct level and install reservoir cover.
5. Raise vehicle and suitably support.
NOTE: If the Powermaster III Unit being bled is a replacement part or there is difficulty when trying to bleed the front master cylinder sections, make sure all air is removed from the master cylinder body by opening the brake pipe tube nuts on the Powermaster III Unit (front two only) approximately 2 turns or until fluid begins to bleed.
(Figure 1) Bleeding Brakes:
6. Bleed right front wheel brake:
^ Attach bleeder hose to bleeder valve and submerge opposite end in a clean container partially filled with brake fluid.
^ Slowly depress brake pedal.
^ Open bleeder valve.
^ To assist in freeing trapped air, tap "lightly" on caliper castings with a rubber mallet.
^ Close bleeder valve.
^ Release brake pedal.
^ Check fluid level and add new brake fluid as necessary.
7. Repeat step 6 until brake pedal feels firm at half travel and no air bubbles are observed in the bleeder hose.
8. Repeat steps 6 and 7 on the left front wheel brake.
NOTE: Turn the ignition off if pump motor runs for more than 60 seconds, refer to Pump, Brake Fluid / Testing and Inspection.
9. Turn ignition to the "Run" position without starting the vehicle. Allow the pump motor to run to pressurize the accumulator.
10. Bleed right rear wheel brake:
^ Attach bleeder hose to bleeder valve and submerge opposite end in a clean container partially filled with brake fluid.
^ Open bleeder valve.
^ With ignition on, slowly depress brake pedal part way, until brake fluid begins to flow from bleeder hose. Allow brake fluid to flow for 15 seconds. Do not fully depress brake pedal.
^ To assist in freeing trapped air, tap "lightly" on caliper castings with a rubber mallet.
^ Close bleeder valve and release brake pedal.
^ Repeat preceding two substeps until no air bubbles are seen in the bleeder hose.
^ Check brake fluid level and add new brake fluid as necessary.
^ Fill the rear chamber to approximately 25 mm (1 in.) below full mark at this intermediate stage with system charged.
^ Repeat steps 9 and 10 on the left rear wheel brake.
^ Lower vehicle.
11. Bleed Powermaster III Isolation Valves:
^ Attach bleeder hose to bleeder valve on inboard side of Powermaster III Unit and submerge opposite end in a clear container partially filled with brake fluid.
^ With ignition still on, apply light force to the brake pedal.
^ With the brake pedal applied, slowly open bleeder valve and allow brake fluid to flow until no air is seen in the brake fluid.
^ Close bleeder valve when brake fluid begins to flow without air bubbles.
^ Repeat procedure on outboard side bleeder valve.
12. Bleed accumulator:
^ Turn the ignition off and depressurize the Powermaster III Unit. Wait two minutes for air to clear from the brake fluid in the reservoir.
CAUTION: Never check brake fluid level without fully depressurizing the Powermaster III Unit or overfilling will result.
13. Remove reservoir cover and check brake fluid level in both reservoir sections. Using clean DOT 3 brake fluid from a sealed container, fill the reservoirs to the proper level as necessary.
14. Install reservoir cover and snap all four cover tabs in place on reservoir.
15. Before turning the key to run, manually apply brake pedal with a jabbing (sharp rapid apply) using full force three times.
16. Turn the ignition to "Run" and allow the pump motor to run.
NOTE: Turn the ignition off if pump motor runs for more than 60 seconds, refer to Pump, Brake Fluid / Testing and Inspection.
17. Bleed booster section of Powermaster III Unit:
^ Connect tool# 094-00101. Turn ignition to "Run". Without starting the engine, allow the pump to charge the accumulator. When the pump has stopped, perform the "Solenoid bleed and checkout" test.
^ If 094-00101 is not available, depress the brake pedal with moderate pressure and turn ignition to "Run" without starting the engine for 3 seconds. Repeat this "Off/ Run" procedure 10 times to cycle the solenoids.
Inspection:
a. Apply brake pedal and note brake pedal feel and travel. If brake pedal feels firm and smooth without excessive travel, system is properly bled. Proceed to step 18.
b. If brake pedal feel is soft or spongy or pedal travel is excessive, rebleed front brakes. If excessive brake pedal travel continues, first check the fluid level, then check for leaks throughout the brake system.
NOTE: Excessive brake pedal travel exists when (while driving the vehicle) braking action does not start until after the first 38 mm (1.5 in.) of pedal travel.
c. If a "bump" is noted upon initial pedal apply, or pedal apply does not feel smooth and uniform:
^ Raise the rear wheels approximately 75-150 mm (3-6 in.) off the ground.
^ Depress the brake pedal with moderate pressure. Turn the ignition to the "Run" without starting the engine for 3 seconds. Turn the ignition back to the "Off" position. Repeat this procedure 5 times.
^ Turn the ignition "Off" and depressurize the Powermaster III Unit. Wait 2 minutes for air to clear from the brake fluid in the reservoir.
^ Lower the rear wheels.
^ Pressurize the system by turning the ignition key to the "On" position without starting the engine.
^ Bleed isolation valves, refer to steps 11 through 13.
18. Road test vehicle and note pedal travel and feel.