Brake problem?

Well, I can't seem to figure out why the rotors keep thumping on my car. First time I replaced them with new pads-no problem. Smooth braking, a couple months later, they started thumping again. Okay, likely a caliper sticking. Replaced both calipers, pads and rotors, checked for smooth operation-ok. Now it's been a couple of months and guess what? Thump, thump, thump. I know it's likely a flex hose partly closed or something but has anyone else run into this? It's a 2000 with 130,000 km. Thanks in advance

Are you having the rotors turned before you replace them? Are you torquing the lug nuts to the proper spec? Are the hubs mating surface to the rotor clean/rust free? If you have aluminum wheels are the wheel to rotor mating surface corrosion free?

what do mean on thump thumb? or is it calipers locking up? if so i'd check the front rubber brake lines they colaps inside. but if your buying cheap roters i'd think that's your problems because if there stacked wrong they were probably warped when you bought them.

Thanks for the replies, well no I never get new rotors turned-wasn't that for old school rotors, or for today's larger vehicles? I have been using cheap rotors, but, I have used the same kind over the years, for all the different Sunbirds, Sunfires, Cavailers, Grand Am, etc, and this if the first time I've had an issue. They are aluminum wheels but appear to be corrosion free. Must be bad brake line-maybe.

Turn the rotors. Torque the lugnuts!

At the dealer lot I used to work at, they turned aftermarket rotors right out of the box, because they came warped.

Turn, proper torque, etc.....

Unless you want to try GM original rotors, but it may not be worth the extra cost.

And why would you replace a rotor that`s a few months old without trying to turn it?