Check Valve

Remove the vacuum tube from the vehicle. Check the vacuum tube for cracks, splits and collapsed sections. If no concerns are found, using a suitable adaptor, connect a hand operated vacuum tester to the brake booster end of the tube. Reduce the pressure to 40.5 kPa (12 in-Hg). The pressure should hold to this setting. If the pressure cannot be reduced or does not hold install a new check valve.