Hydraulic unit, replacing: Removal

Preparations 

Fig 1: Checking Power Brake Booster

Courtesy of VOLVO CARS OF NORTH AMERICA.

Switch off the ignition

Place paper under the ABS hydraulic modulator as protection against brake fluid spillage.

Depress the brake pedal a few times so that no vacuum remains in the servo unit.

Clean the brake pipes terminals at the ABS hydraulic modulator and master cylinder