On aggressive braking, the front starts rattleing

[00grand-am]

The car is a 2000 Pontiac Grand Am SE, 4 cyclinder, 90,XXX miles.

Just got this car. And what i've noticed if i use aggressive braking, the front starts to rattle, vibrate and pulsate through the brakes. I think its the shocks since the front suspention seems to flot and sounds like the shocks are bottoming out. Could this be the shocks?

I already took off all the tires and nothing seems lose so my only guess is its the front struts that is causeing these rattleing, vibrate in the front of the car. The suspention/shocks seems to absorb the rattles/vibrations but it does make a loud noticable kind of bumping/rattle/vibrate sound. Has anybody experiancd this before?

[crazy Jim]

You probably do have some strut bushings worn but you main prob is the brakes. Turn or replace the rotors, replace the pads, hand torque the wheel lugs to the specified torque when you reinstall the wheels so as to no distort the rotors and then break-in the new pads by gettting them slightly warm and alllowing them to cool three times. This should take care of the shimmy/pulsating sensation you are getting.

[00grand-am]

Thanks i'll check the struts. The brakes looked ok when i checked them, I'll have to check the rotors, thanks.

[xeroinfinity]

00grand-am, sounds like your rotors are warped!

This happens frequently on several makes and models.
The rattling is probly the calipers and probley the whole front end(suspension). It can sound and feel as if the thing is going to fall apart when stomping on the brakes extremely hard.

Most new pads recommend no emergency stops or hard stops for 200 miles.
Thiers no need for special break in's unless the new rotors & pads recommend it.

Best bet is to have the rotors and pads replaced ,
and make sure the slide pins on the calipers are greased and slide smoothly.

Now as crazy_jim stated you could have a busted strut bearing plate or springs.
You can jack the wheel off the ground and pulling on the spring can tell you a little more.
Also See if they turn, they should Not !

hope that helped!

PS
if you do the brakes, bleed the hell out of them!
I also have this big write up on brakes and problem solving if you need .

[GMMerlin]

Originally Posted by 00grand-am

The car is a 2000 Pontiac Grand Am SE, 4 cyclinder, 90,XXX miles.

Just got this car. And what i've noticed if i use aggressive braking, the front starts to rattle, vibrate and pulsate through the brakes. I think its the shocks since the front suspention seems to flot and sounds like the shocks are bottoming out. Could this be the shocks?

I already took off all the tires and nothing seems lose so my only guess is its the front struts that is causeing these rattleing, vibrate in the front of the car. The suspention/shocks seems to absorb the rattles/vibrations but it does make a loud noticable kind of bumping/rattle/vibrate sound. Has anybody experiancd this before?

Vibration during braking is caused by excessive thickness variation of the front rotors.

[00grand-am]

Thanks for the help. Last night my older brother came over and we were talking and i asked him about the Grand Am and he said that his car just started doing the same thing on his Honda. He said balencing the tires helped and when he talked to a mechanic he told him that it could be the lug nuts are tightened too much or that the rotors need resurfacing or new brakes as was said here. So for right now, since the problem doesn't seem to be big, when able i'll get the brakes done and tires balenced. My younger brother who is the owner of the Grand Am has been driving the car and he says the car stops great and he doesn't other then on aggresive brakeing.