Pneumatic brake booster having simplified mounting properties and vehicle with a brake booster of this kind

The servomotor has a cover (6) equipped with a plate (30) having angular sectors (36) mounted at a spacer fixed at a firewall of a motor vehicle in an engine compartment. The firewall separates the engine compartment from a passenger compartment. A tubular sleeve (44) connects the cover in an air tight manner to the firewall for preventing passage of water and air to the passenger compartment from the engine compartment. Independent claims are also included for the following: (a) a method of fabrication of a servomotor (b) a motor vehicle.