GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 1999 🢒 SL2/SC2/SW2 🢒 Brakes 🢒 Antilock Brake System 🢒 Brake Pressure Modulator Valve Replacement

Assembly Procedure

    Object Number: 904541 Size: SH

    Important: Do not attempt to repair damaged motor packs or modulator assemblies. Other than modulator drive gear replacement, repair of these assemblies is not authorized. Do not lubricate or oil motor pack assembly.

  1. Remove 2 gear cover to modulator TORX™ head screws and separate gear cover from modulator.

    2. Object Number: 904647 Size: SH

    Important: If only the motor pack is being replaced, perform step 3 of this disassembly procedure then perform steps 6 through 9 of the assembly procedures. If removing the master cylinder, perform steps 3 through 6 of this disassembly procedure then perform steps 1 through 5 and 8 and 9 of the assembly procedures.

    Important: If the modulator is the only unit being replaced, mark the modulator drive gears before removal so that they can be installed onto new modulator in the same location.

  2. Remove 3 modulator drive gear to modulator drive shaft retaining nuts and remove gears from modulator.

    3. Object Number: 904719 Size: MH
  3. Remove 2 motor pack to modulator TORX™ head screws and separate motor pack from modulator.
  4. Remove 2 modulator to master cylinder through bolts and separate modulator from master cylinder.
  5. Remove 2 transfer tubes with O-rings from master cylinder or modulator.
  6. Remove through bolt O-rings from master cylinder and modulator.

Disassembly Procedure

    Object Number: 904719 Size: MH
  1. Lubricate new transfer tube O-rings with clean brake fluid.

    2. Important: New O-rings and transfer tubes must be used when performing this step.

  2. Install transfer tubes (with O-rings) into modulator by pressing in tubes by hand, until bottomed in modulator.
  3. Lubricate new through bolt O-rings with clean brake fluid and install into master cylinder and modulator.
  4. Install master cylinder onto modulator.
  5. Install 2 modulator to master cylinder through bolts.

    6. Tighten
    Tighten modulator to master cylinder through bolts to: 16.5 N·m (146 lb in)


    Object Number: 904329 Size: SH
  6. Position modulator drive gears onto drive shafts and install three gears to drive shaft retaining nuts.

    7. Tighten
    Tighten gears to drive shaft retaining nuts to: 8.5 N·m (75 lb in)

  7. With the modulator upside down and the gears facing you, rotate each gear counter-clockwise until movement stops. This procedure will position the pistons very close to the top of modulator bore, simplifying the brake bleeding procedure.
  8. Position motor pack onto modulator aligning the 3 motor pack gears with the modulator gears and install 2 motor pack to modulator TORX™ head screws.

    9. Tighten
    Tighten motor pack to modulator TORX™ head screws to: 4.5 N·m (40 lb in)

  9. Install gear cover onto modulator assembly with two TORX™ head screws.

    10. Tighten
    Tighten gear cover to modulator assembly screws to: 2.75 N·m (25 lb in)