Power Brake Booster Function Test (Vacuum, Hydro-Boost & Hydro-Max): Accumulator
- Start and run the engine.
- Stop the engine.
- Apply the brakes. The accumulator in the Hydro-Boost power brake booster should retain enough pressure for at least two power-assisted brake operations. If no power assist is felt, install a new Hydro-Boost power brake booster and retest the system.