Where can this knocking be coming from? [Archive] - GrandAmGT.com Forum

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srosenau20
08-20-2009, 02:43 PM
Hey guys,

I got this knocking noise in the front of my 2001 Pontiac Grand Am GT coupe. It only occurs when Im' braking. It used to hit fast when I broke at high speeds under 30mph (when I could hear it) and then as I slowed down, while braking, the hit slowed down. Seemed like every wheel revolution. Well, I replaced the rotors and I thought that took care of it.

However, its still there. Just doesn't sound like every wheel revolution anymore. Usually does it when I'm braking, and right when I let go of the pedal. If I'm at a stop and I press the brake, you can also hear it. Any ideas of what it might be? Thanks everybody.

Scott

burgett2103
08-20-2009, 03:25 PM
is it knocking just when you brake? or does it sound like its winding down

srosenau20
08-21-2009, 08:29 AM
Usually just when I apply my foot to the brake. I don't know what it could be. Braking power is fine, no vibration when I brake at high speeds. I'm stumped.

hahano404
08-21-2009, 02:59 PM
what all did you replace? and did it get lighter than came back? or did it change tone? and by usually.... do you mean only when you brake or is there other times it happens?

burgett2103
08-21-2009, 03:22 PM
if it sounds like its winding down then it's your rotors cause mine do that too.. and it's not a bad thing sounds kinda cool bra

hahano404
08-21-2009, 03:34 PM
if thats the case, than its from a hard compound pad ie ceramics or high metallics, against a hard rotor. different brands have differnt methods of production. its normal.

srosenau20
08-21-2009, 11:58 PM
well they're semi metallic pads. New rotors. It is not a winding down sound, that would be pretty nice. But its not. It's like a soft tap, maybe a knock, mostly every wheel revolution. It's not as loud as if once was now that I have replaced the rotors.

hahano404
08-22-2009, 09:31 AM
check clearance between dust shield. the flex in braking may have it coming it contact with rotor. i know its a pain to keep pullin the wheels off. while your down there though make sure your not getting any tire rub from the the car leanin forward during braking.
hmm. how old are the pads and who was the manufacture if you can remember?

srosenau20
08-23-2009, 08:43 AM
Pads are only a few months old. Made by Duralast bud.

westerndragon
08-23-2009, 09:16 AM
Check you caliper harness bolts for tightness. I lost one once in the front and had a similar knocking sound from when the caliper was slipping back and forth. and it was only happening during harder braking like down hill or from a high speed it was the lower bolt on mine.

hahano404
08-23-2009, 12:36 PM
yea sounds like another thread on here but forgot to mention torque the bolts down, but did on the other thread.

i have also noticed that i could go through duralasts with-in a month so id check em as well.