V70 XC AWD L5-2.4L Turbo VIN 56 B5254T (1998)
Vacuum Brake Booster: Description and Operation
Power Brake Booster Overload Relay
DESCRIPTION
The power brake booster overload relay is located between the brake pedal and the master cylinder.
OPERATION
The power brake booster overload relay is of the vacuum-assisted type and enhances the force the driver exerts on the pedal when braking. The
enhancement ratio is 4.5:1. The vacuum is derived from the partial vacuum in the engine inlet manifold. The connection between the engine inlet
manifold and power brake booster overload relay has a non-return valve (1). This prevents air flowing back into the power brake booster overload
relay if there is no partial vacuum in the inlet manifold. The pedal sensor (2) is mounted on the power brake booster overload relay.
