Brake Booster Inspection

Special Tools Required Vacuum gauge 07404-5790301 Pressure gauges 07406-5790201 Attachment 07410-5790101 Tube joint adapter 07410-5790501 Pressure gauge joint pipes, 10 x 1.0 mm 07510-6340101 Oil pressure attachment 070AJ-S3V0100 Oil pressure hose 07FPJ-7520100 Pressure gauges set 07YAJ-0010410 Leak Test Install the vacuum gauge (A) between the brake booster and check valve. Start the engine, adjust the engine speed with the accelerator pedal so that the vacuum gauge readings show 40.0−66.7 kPa (300−500 mmHg, 11.8−19.7 in.Hg), then stop the engine. Read the vacuum gauge. If the vacuum reading decreases 2.7 kPa (20 mmHg, 0.8 in.Hg) or more after 30 seconds, check following parts for leaks. Check valve Vacuum hose, pipe Seals Brake booster Master cylinder NOTE: Do not try to disassemble the brake booster. Replace the brake booster as an assembly with a new one. |

Function Test Install the vacuum gauge the same as the leak test. Connect the oil pressure gauges (A) to the master cylinder using the attachments (special tools) as shown. For ABS type, bleed air through the valves (B). Start the engine and let it idle. | VSA type ABS type

1. Have an assistant depress the brake pedal with a 98 N (10 kgf, 22 lbf) and 294 N (30 kgf, 66 lbf) of pressure measuring with a commercially available pressure gauge (A). The following pressures should be observed at the pressure gauges in each vacuum.
   Vacuum booster vacuum kPa (mmHg, in.Hg) | Brake pedal pressure N (kgf, lbf) | Master cylinder oil pressure kPa (kgf/cm 2 , psi)
   0 (0, 0) | 98 (10, 22) | 0 (0, 0)
   294 (30, 66) | 545 (5.6, 79)
   66.7 (500, 19.7) | 98 (10, 22) | 5,015 (51.1, 727)
   294 (30, 66) | 9,570 (97.6, 1,388)
Inspect the master cylinder for leaks if the readings do not fall within the limits shown above. |

Booster Check Valve Test Disconnect the brake booster vacuum hose (check valve built in) (A) at the booster side. Start the engine, and let it idle. There should be vacuum available. If no vacuum is available, the check valve is not working properly. Replace the brake booster vacuum hose and check valve, and retest. |