Between vacuum pump and power brake unit

1. Remove the vacuum hose on the vacuum pump side. (See VACUUM HOSE REMOVAL/INSTALLATION .)
2. Blow air into the vacuum hose from the power brake unit side using your mouth and verify that the air flows to the vacuum pump side, then blow air from the vacuum pump side and verify that the air does not flow to the power brake unit side.

Fig 1: Blowing Air Into Vacuum Hose From Power Brake Unit Side

Courtesy of MAZDA MOTORS CORP.

• If there is any malfunction of the inner check valve, replace it together with the vacuum hose as a single unit. (See VACUUM HOSE REMOVAL/INSTALLATION .)