#
POWER BRAKE UNIT INSPECTION

BME041143800W01

## Power Brake Unit Function Check (Using Gauges)

1. Connect the SSTs or equivalent, vacuum gauge (A), and pedal depression force gauge (B) as shown. Bleed the air from the SST gauges before performing the following tests.

2. Check for vacuum loss with unloaded condition as follows.

  (1) Start the engine.
  (2) Stop the engine when the vacuum gauge reading reaches 66.7 kPa {500 mmHg, 19.7 inHg}.
  (3) Observe the vacuum gauge for 15 seconds. If the gauge shows 63.4-66.6 kPa {475-500 mmHg, 18.7-19.6 inHg}, the unit is operating.

3. Check for vacuum loss with loaded condition as follows.

  (1) Start the engine.
  (2) Depress the brake pedal with a force of 200 N {20 kgf, 44 lbf}.
  (3) With the brake pedal depressed, stop the engine when the vacuum gauge reading reaches 66.7 kPa {500 mmHg, 19.7 inHg}.
  (4) Observe the vacuum gauge for 15 seconds. If the gauge shows 63.4-66.6 kPa {475-500 mmHg, 18.7-19.6 inHg}, the unit is operating.

4. Check for hydraulic pressure as follows.

  (1) If fluid pressure is within the specification when the engine is stopped (vacuum 0 kPa {0 mmHg, 0 inHg}), the unit is operating.

Pedal force | Fluid pressure
--- | ---
200 N {20.4 kgf, 44.9 lbf} | 790 kPa {8.06 kgf/cm2, 115 psi} min.

  (2) Start the engine. Depress the brake pedal when the vacuum reaches 66.7 kPa {500 mmHg, 19.7 inHg}.

  • If fluid pressure is within the specification, the unit is operating.

Pedal force | Fluid pressure
--- | ---
200 N {20.4 kgf, 44.9 lbf} | 8,830 kPa {90.04 kgf/cm2, 1,280 psi} min.