Car shakes when braking

[Miguel92.3000GT]

Hey guys. I have an issue with my car. It's a 92 3000gt. For some strange and unknown reason my car shakes when braking. I already changed my front brakes and rotors I also balanced and aligned all four tires. So my question is what else can be causing my car to shake when braking? Any and all help appreciated.

[CoopKill]

Did it shake before the brake change?

When did it start shaking?

What had you done before the shaking began?

High speed shake, low speed shake, or at all times?

If it started after changing the rotors, what rotors did you use?

[Miguel92.3000GT]

Did it shake before the brake change?
No it didnt shake before the change.

When did it start shaking?
After the brake and rotors were replaced.

High speed shake, low speed shake, or at all times?
Its definitely a high speed shake like above 40 but a lot worse around 80.

If it started after changing the rotors, what rotors did you use?
I used the ones from Advance Auto parts.

[CoopKill]

R/T93 had this issue as well. He found that the rotor was sagging out of center on the hub when he removed the wheel. He now has to reach up and center the rotor while tightening the wheel in place.

Sounds odd, but this is what solved his issue, which sounds very much like yours... He used an upgraded rotor though.

[Miguel92.3000GT]

Ok thanks. Will definitely check my rotors and see if that it. Will post results later.

[speedy25]

Loose front end components can cause your troubles too, but since you stated it wasnt there before, its something that was a part of your brake work.

-SP

[ChargerX3]

Jack up the car and wiggle the front wheels with your hands in all directions. They should not budge at all. If they do then backtrack from there.

[Miguel92.3000GT]

I checked my rotors but they are good and in place. But I did notice that one of my wheel studs is loose. Can this cause shaking. And can the cv axle cause this?

[stealthee]

If the stud is loose then the tire isn't tight and yes that can cause wobbling.

[Miguel92.3000GT]

But wouldnt the lug nut keep it tight

[speedy25]

Also check to make sure there is no debris on the hub or inside the rotor where it contacts the hub.

-SP

[Miguel92.3000GT]

Sorry guys I stopped driving the car since it started shaking but now I need to fix the problem. I took a pic of a frint end component that looks weird and sort of bent. It the part right in the center.

[ChargerX3]

Everything looks ok to me. Are you talking about your sway bar?

[Miguel92.3000GT]

yeah the sway bar. I read that if the sway bar bushings are bad it can cause the car to shake violently when brakig, simulating warped rotors.

[stealthee]

I wouldn't beleive that. The sway bar is just an anti sway bar. You can completely remove it and it wont affect braking. All the sway bar affects is body roll.

[Miguel92.3000GT]

I really dont know what can be causing the shake its starting to become irritating.

[stealthee]

You yourself said it didnt start until AFTER the brake change. Something was done wrong there. Go back over your work. Whatver is causing it, its not the swaybar.

[Bluejediz]

$5 says its one of these two things:
#1. There's rust buildup between the rotor and the hub....I always buzz mine clean with a die grinder or at least take some sandpaper to it.
#2. Most new rotors are warped....all it takes is a good drop on a hard floor and youll get a pulsation. I always cut brand new rotors before they go on a car....not saying all rotors will pulsate from the manufacturer, but A majority are a little off...depending on how bad they are, this can cause a pulsate.

My 2 cents: Take the rotor off and clean the hub. If the pulsate is still there, get the rotors machined at a good shop.

[Miguel92.3000GT]

Ok will check the rotor and the hub, while I have it off Ill inspect everything just to make sure I didnt mess up somewhere. Meanwhile Ill post pics of my rotor the shaking has caused my driver side rotor to engrave a line throughout the whole rotor but the passenger side looks fine

[stealthee]

That rotor is not seated correctly.

[Vince86]

do you have to use hub centric rings for those rims? if so did you remember to install them back on the hub?

[Miguel92.3000GT]

I dont have any on, at least not that im aware of. Will check and see and if not Ill get some either way.

[Vince86]

They are only needed if the diameter of the hub is different than the diameter of the opening of the mating surface of the rim. In my sig I have the Saleen mustang rims, for those to work I had to buy a hub-centric ring that filled a tiny gap between the mating surfaces otherwise symptoms such as yours would happen. best way to find out is to use a digital caliper on the hub and the opening of the rim and compare the sizes.

But you say it didnt happen before the brake change and if you had those rims on before and were the person who originally bought and installed them then this is not your issue. If you bought the car with these rims on it and then replaced some of the parts you listed then this could be your problem. They can usually be found on ebay but you must measure to get the right sized ones.

[1993ttrt]

I had stock rims when it started shaking then switch to my Konigs

[STiedVR4Guy]

Just to add to this, I have had this issue for a long time and it was just recently brought to my attention something I have seen before. Hub centric rings for aftermarket wheels are needed. This never even crossed my mind but you can get them at a local discount tire or other tire/wheel vendor.

Here's a pic, I'm going to put them on this weekend probably to see if this is actually my issue, other than that I have replaced EVERYTHING on the front end.....

http://i526.photobucket.com/albums/cc346/TitanGenesis/IMG_20110802_145439.jpg

NOTE: this part number is not for ALL aftermarket wheels, please make sure they look your wheels up.

[stealthee]

Hubcentric rings are not NEEDED. I have never used them, and have never had a problem.

I guarantee you the OP's issue lies with the rotor not being seated properly.

[STiedVR4Guy]

Hubcentric rings are not NEEDED. I have never used them, and have never had a problem.

I guarantee you the OP's issue lies with the rotor not being seated properly.

I find it hard to believe that the many many times I have had my wheels off and on my car over and over and 3 sets of rotors some of them turned but 2 sets brand new have ALL managed to warp/cause shaking less than 200 miles after installation is JUST because of not seating them properly, I have made sure to star pattern my lugs down over and over and make sure a TQ wrench is used to proper ft/lbs.

I'm sure you know your shit in and out on these cars Stealthee (I have taken your advise MANY MANY times on these forums and those of the past) but I just can't believe that is the ONLY issue. I've had wheels off and on of all of my cars including my STi which I beat the piss out of and NONE of them have had this much of a problem with it.

[stealthee]

I've had the same set of rotors on my Stealth since 07. Still not an ounce of wobble or shake with braking or anything. My 17's came off a Mustang and I never got hubcentric rings, and never had a shake.

Look at the pictures the OP posted. One of the rotors has a groove the whole way around. I have seen it on more than one occasion where teh rotor wasn't all the way seated and was not being grabbed right by the caliper. Also he said his issue didn't start until he did the brake swap.

[STiedVR4Guy]

Ok, so 2 brand new sets and 2 turned sets have all just been me screwing up mounting the rotor every single time. Got it.

[J. Fast]

So was that the fix, remounting the rotors? Warped rotors? Centric rings, or were your brake pads not shimmed evenly?

[marshallh]

This weekend I tore into my frontend; new balljoints, inner and outer tie rod ends, turned rotors, new pads from NAPA, new cv axles.

The horrible brake shudder I used to have is completely gone. I have hubcentric rings on my wheels, and torqued them in a star pattern with a torque wrench.

[DrGonzo]

Unplug the ABS system and see if that fixes the issues. A bad pump will cause shaking really bad! Pulled the ABS fuse and no more shaking!!!

[Coxnifer]

Lots of great ideas in here! Gotta figure out why mine shakes too.

[STiedVR4Guy]

Hub Centric rings fixed my shake at all speeds.