Fits Vauxhall Vectra MK3 1.9 CDTi Genuine Delphi Brake Master Cylinder. We apologise in advance for any inconvenience caused. The Master Cylinders purpose is to transfer the pressure from your right foot into hydraulic pressure enabling your Brake Caliper to clamp fully onto your Brake Disc allowing you to stop. Over time they begin to fade and wear, which is evident in your vehicles braking capabilities. It is recommended that you fully maintain your braking system, as they play a vital role in your safety, and can potentially be an MOT failure.