Accumulator, Modulator & Abs Pump (Power Unit) Bleeding
- Remove service cap from maintenance bleed screw on modulator unit. Attach wrench to maintenance bleed screw. Place one end of a rubber tube over maintenance bleed screw. Place other end of tube in a suitable container to collect fluid. See Figure.
- While holding tube, slowly open bleed screw 1/8 to 1/4 turn to release pressure. Have an assistant start and idle engine. Allow fluid to flow from tube until no air bubbles are present. Close bleed screw and turn engine off.
- Check reservoir fluid level. Fill reservoir as required. Repeat procedure as necessary to ensure no air is in system. Tighten bleed screw to specification. See TORQUE SPECIFICATIONS . Start and idle engine. Depress brake pedal. If brake system will not hold pressure, the hydraulic system still contains air. Go to next step. If system holds pressure, bleeding procedure is complete.
- Leave bleeder tube attached as in steps 1) and 2). Connect a piece of 3/8" (10 mm) hose to the pressure side of a manual vacuum pump. Remove the modulator reservoir cap. Connect the other end of the hose to the reservoir insert. Hold hose and insert firmly in place. Have an assistant start the engine.
- While engine is idling, apply pressure to the system until resistance is felt in the pump. Have assistant turn the engine off and slowly open the bleed screw until all pressure is released. Close the bleed screw. Repeat procedure 5 times to ensure air pocket is purged from modulator. If ABS control unit has a stored Diagnostic Trouble Code (DTC), clear DTC from control unit memory. See CLEARING DTCs under SELF-DIAGNOSTICS.