Delayed thump after braking from front of gtc

[bigsadie]

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 can hear coming from front of car. Any ideas. The car is still under warranty. I at least want to go back to the garage with a rough idea of what I'm talking about. Any help greatly appreciated. Thanks.

[niteram]

It could be a number of things.
does it happen when you take your foot off the brake, or when you pull away?
if its when you take your foot off the pedal, then it seems like it's the system de-pressurizing, maybe a loose bracket or similar, maybe a sticking caliper slider?

[bigsadie]

Thanks for that. Its when i take foot off brake then there is a delayed thump. Also is it normal to hear water slooshing about from back end. Ive had an astra and a vectra both for ten years and never had as much doubt in the car. Gtc was my dream car and now........ha ha. Thanks.

[Hummelshøj]

"Also is it normal to hear water slooshing about from back end."

Maybe this could be the diesel/petrol you can hear slooshing about in the tank. I can hear it too in my GTC.

[J1ODYA]

It's the fuel tank... the tank is missing something which means when almost full You'll hear the fuel. Drive more gentle lol

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[Rusty2009]

Not sure on brakes, the water could well be the tank (missing baffles) or it could be water in the doors.

Check the bottom of your doors there should be 2 drain holes, sometimes they have rubber in them just pull them out.

[bigsadie]

Thanks guys, I have an astra gtc sri 2.0 CDTI.
I did think it was the tank. Maybe i should drive slower. Ha ha. I filled up the fuel so maybe it was the tank. If this is normal then I will just have to play my tunes louder!Will check the doors also just to be sure. Thanks for that. Its so difficult to find a garage you can trust. Cheers for the help.

[Rusty2009]

My 2.0cdti fuel sloshes when full.