Need advice on brakes

[KingLazy]

Still a newbie. Sent my car in to change the disc brakes, alternative german parts. Mechanic changed the front and tested it but there was loud knocking noise that sounds literally like somebody whacking it with a hammer. He thought it was faulty, so he got a new set and tried again. Same thing. Last resort, skimmed my old disc and put it back. Warbling has stopped. And it works. However in future, any advice on brakes and what the hell was that knocking noise?

 

[skar19]

not sure what the knocking noise is, maybe the disc couldnt fit properly , best to go for original parts,

 

[KingLazy]

Hi Skar,

I was told original disc brakes do not come with warranty as well?
Is that true?