Knocks when braking

[TdotAlero]

First, I apologise if thise has been previously covered. I searched and couldn't find anything on it.
This just started happening today. I take thise bumpy road to work, untill it connects to a normal, 3 lane road. All of the sudden this knocking noise comes up. I will try to describe to my best, what it sounds like. Something like this:
Driving on bumpy road - quiet, no noise.
Driving on smooth road - quiet, no noise.
Accelerating - quiet, no noise.
Apply brakes - one knock, nothing after.
Stopped on the traffic lights - quiet.
Release brake pedal, apply gas - one knock, quiet after.
And so on, and on.
Tried pumping brake, no knocks. Only when as described above.
I have recently replaced all four rotors and pads as well as both front springs. Could this be connected ? I just want to get an idea of what to pay attention to tomorrow, when I put my car on a lift.

[lord2heart]

seeing how it "knocks" when you apply the brake and let go off it it. there could be a problem with your brake caliper??? such as the piston?

making an educated guess here

[TdotAlero]

seeing how it "knocks" when you apply the brake and let go off it it. there could be a problem with your brake caliper??? such as the piston?

making an educated guess here
Wouldn't that make knocking sound as I "pump" the pedal, while in park ?

[alero_bmxer]

did you tighten all the caliper bracket bolts? just asking cause we had a car come into work today and the owner forgot to tighten them and the caliper became lodged against the wheel while driving and put a 6x6 hole on the inside of the rim.

[lord2heart]

did you tighten all the caliper bracket bolts? just asking cause we had a car come into work today and the owner forgot to tighten them and the caliper became lodged against the wheel while driving and put a 6x6 hole on the inside of the rim.

i actually had this happen to me one morning when i was going to school a year ago:glare: and 1 bolt came out and the caliper was grinding against the inside rim

[clutch1]

Yeaa, pull them wheels off and check out to make sure the calipers and brackets are all tight..

[Redog]

As soon as I read the title of your thread, I knew the caliper bolt backed out ;)

Fix it NOW!! My co worker had this happen to his Envoy and the caliper fliped out and destoryed the rim

[alero_bmxer]

Fix it NOW!! My co worker had this happen to his Envoy and the caliper fliped out and destoryed the rim

haha it was even on an envoy

[TdotAlero]

Thanks for response. I guess I was "too easy" on those bolts, trying not to break them.

[Lucalare]

Thanks for response. I guess I was "too easy" on those bolts, trying not to break them.

Bolts on brakes and suspension components are made for lots of torque, no need to be gentle.

[lord2heart]

your life depends on those brakes man lol better get them nice and tight than worry breaking them

[TdotAlero]

I tightened the bolts (impact gun set at 125lbs). Knocking stopped, but during a 1 hour drive I heard it again twice during sudden breaking.

[AlbinoMonkeyRat]

Bolts on brakes and suspension components are made for lots of torque, no need to be gentle.
except for the bolt keeping the brake line attached to the caliper...that is the only one to be SUPER careful with. I broke one of these and it can be around 3 days for an Autozone store to get one for you if they don't have any in stock.

[comanche]

Hmm.

It's still happening? And you checked ALL the bolts?

Maybe a really super bad lower ball joint?

[TdotAlero]

Actually been driving all day today and no knocking at all. So I believe that was the problem.
Thanks to everyone for help.