Answer by  
                                                                                          Xceptional (642)
                                                            
                          
                          
                                                          This is a fairly broad question becomes there are many different models of your type of car. I would either consult a mechanic personally, or refer to your user manual. You can either completely replace the brake pedal, or get a "prop kit" to try to re-elevate it and prevent further sinking.