Vacuum Brake Booster: Testing and Inspection
Check function of brake assist in brake booster; from 12.01
With engine running, depress brake pedal to ensure full vacuum boost.
When brake pedal is depressed, a "clicking sound" must be audible, so that the mechanical brake assist is activated.
The brake pedal can now be partially released and pressed again with less force.
It is not possible to repair the brake assist, the complete brake booster must be replaced.