Hi I was wondering if anyone could give me some advice. I bought an Astra gtc 2ltd in March 13 plate. Recently I have noticed that there is a thump coming from font of car. Only happens after I brake. For example if I brake and come to a stand once I remove my foot from brake a few seconds later there is a thud. This happens when braking and pulling away at low speeds only. If the car is stationery and in neutral and I press the brake lever remove my foot a few seconds later a loud thud that I c