1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4FACTORY OEM SERVICE PROCEDURE

ABS Modulator Assembly (Priming)

Clean master cylinder reservoir cover and surrounding area. Remove reservoir cap. Ensure reservoir is full. Install reservoir cap. Attach a clear hose to rear bleeder valve and submerge other end of hose in a container of clean brake fluid. See Figure. Slowly open rear bleeder valve. Depress brake pedal until fluid begins to flow. Close valve and release brake pedal. Repeat procedure until no air bubbles are seen in hose. Repeat procedure for front bleeder valve.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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