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Home >> Mitsubishi >> 2004 >> Lancer Evolution >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 4 (Disc - SPORTBACK) >> Testing >> Power Brake Booster >> System Check
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System Check

WARNING: This page is about a different variant/trim than selected.
  1. Run engine for 1-2 minutes. Shut engine off, and depress brake pedal several times with normal pressure. If pedal height gradually becomes higher with successive applications, power brake booster is okay. If pedal height remains steady, power brake booster is not operating properly. Go to next step.
  2. With engine stopped, depress brake pedal repeatedly until pedal height no longer falls. Hold brake pedal down, and start engine. If pedal moves downward slightly, power brake booster is okay. If pedal height does not change, power brake booster is not operating properly. Go to next step.
  3. With engine running, press and hold brake pedal. Shut off engine. Hold brake pedal for 30 seconds. Brake pedal height should not change. If pedal rises, power brake booster is not operating properly. Go to next step.
  4. If brake booster operation is not as specified in each step, disconnect vacuum hose at brake booster, and check for sufficient vacuum with engine running. Check brake booster check valve operation. Repair or replace as necessary.
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