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Functional Test

  1. Check master cylinder fluid level and hydraulic system for leaks. Place transaxle in Neutral or Park, turn ignition off and apply parking brake. Pump brake pedal several times to eliminate vacuum from system, and hold pedal in depressed position.
  2. Start and idle engine. If vacuum system is functioning properly, pedal moves downward under constant foot pressure. If no pedal motion is felt, vacuum booster is not functioning properly. Go to next step.
  3. Run engine for at least one minute and turn ignition off. Depress brake pedal several times. Booster is okay if pedal stroke is long at first and becomes shorter with each stroke. If stroke does not shorten, check for a damaged, restricted or improperly connected check valve vacuum hose. Repair and recheck. Go to next step.
  4. Restart engine. Depress and hold pedal down. Turn ignition off and wait 30 seconds. Booster is okay if pedal height remains unchanged. If pedal height changes, check for a damaged, restricted or improperly connected check valve or vacuum hose. Go to next step.
  5. Connect a pressure gauge to master cylinder output line. Connect a vacuum gauge to booster and a pedal depression force gauge to brake pedal. Bleed air from pressure gauge. Start engine. When vacuum gauge reads 19.7 in. Hg, turn ignition off. Watch vacuum gauge for 15 seconds. Booster is okay if vacuum gauge reads 18.7-19.7 in. Hg. If vacuum gauge reads less than 18.7 in. Hg, proceed to next step.
  6. Restart engine. Apply and hold 44 lbs. (196 N) force to brake pedal. When vacuum gauge reading reaches 19.7 in. Hg, turn ignition off. Watch vacuum gauge for 15 seconds. Booster is okay if vacuum gauge reads 18.7-19.7 in. Hg. If vacuum gauge reads less than 18.7 in. Hg, proceed to next step.
  7. With engine stopped and vacuum gauge at zero, check pressure gauge. Apply 44 lbs. (196 N) force to brake pedal and check pressure gauge. Booster is okay if pressure gauge reads 256 psi (18 kg/cm2 ).
  8. Remove pedal force and start engine. When vacuum gauge reaches 19.7 in. Hg, apply 44 lbs. (196 N) force to pedal. Booster is okay if pressure gauge read 768 psi (54 kg/cm2 ).
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