Alright folks, I have a 97 GTP and when I go to brake with medium to hard it makes a knocking sound. Then after I start moving again I hear the same knock sound. If I accelerate and or brake like a grandma there is no knocking sound. But if I drive normal I hear this knocking sound when I brake and then again when I accelerate. To further describe this sound if I brake (lets say medium hard) it makes the sound but lets say after I have started braking and it made the sound I decide to brake harder, it will knock again. The same goes for when I accelerate.
Today I put it up on the lift and checked everything I could think of and nothing seemed loose or bad except the CV axle, which I thought had some play in it so I replaced it. But with no luck as it still has the same knocking sound. I have in the last year put on KYB struts and mounts all the way around as well as the GM suspension upgrade, along with the HD 12" brake upgrade. And have not had this sound until last week.

I sure would love to hear what you guys think on this. Thanks in advance.

check the pads, if they move at all in the caliper they will knock

check to see if your dp is hitting your sway bar. I had to flip my GMPP's front sway bar because my dp hit it.

Hmmm.....thats a good one....I forgot about that. I thought there was a lot of room there but I didn't check it...thanks

If you are running stock upper mount the engine moves quite a bit.

It's worth a check!!! Thanks for the suggestion, and keep them coming guys.

Well I put it up on the lift again and checked for the down pipe hitting the sway bar (no evidence or marks that would show positive results), checked the engine mounts, grabbed a hold of the caliper and tried to shake it, tried looking again at the control arm bushings (they look normal). None of these things show any wear or evidence of any kind of movement. Just an update folks. Still looking for suggestions. And believe me I know how easy it is to diagnose on the net........NOT!! So thank all who have tried to help.

I will be sure to let you all know what it was when I figure it out.

Did you actually check the tightness of the cradle bolts? Should be 118ft-lbs for front and 122ft-lbs for the rear. Mine were loose (only about 80ft-lbs) when I checked, and they have never been messed with. Really tightened up the front of the car.

I heard about that....I did check them but I didn't know what the toque was for those bolts. I can definitely see how that could be a problem to, it would make sense to move under braking and under acceleration. Thanks for the info!!

if the pads are moving, you aren't going to shake them and cause it (unless you can bench about 1000 pounds)

Alright, I'm with ya.....how do you propose I check the pads to see if they are moving in the caliper like you had advised before? I mean I tried moving them but they don't.

Thanks

only way is to pull the caliper, also look at the rotor and see what the wear looks like, if any grooves then you have a problem