Brakes vibrate/shutter when stopping

[bobby1]

Hi, I have a 2006 Infiniti QX56. When applying the brakes, the front wheels/brakes are starting to shutter and vibrate when trying to stop. In addition the "BRAKE", "SLIP" and "VDC OFF" lights are also on at all times. Any help to adress/fix this problem is appreciated.thanks

[soul_hfk]

well let me welcome you 1st to NICO. BRAKE", "SLIP" and "VDC OFF" alot of times its u mite need brakes or check the fluid level but i would check them both. the reason i know that is cause i had the same thing and the dealer told my that when the pads are low the fluid level drops and sets them off.... the vibrating is the rotores they may need to be turned or you may need new ones

[C-Kwik]

If this occurs with the VDC and slip light is on, then its likely a problem with the ABS computer. Nissan/Infiniti released a TSB that addresses this by having the tech upload new software to the ABS computer. I'd check with your dealer.

In the meantime, if it happens again, no need to panic. The brakes will still work. The vibration is merely the ABS pump activating. Basically anytime you use the brakes when the lights come on, it will engage the ABS everytime you try to stop. It will feel erractic, but you can modulate the brakes somewhat. Generally, the condition goes away if you turn the car off and back on again. So just turn the car off and back on when its safe to do so (perhaps next time you stop for a light). I wouldn't encourage this, but you can also throw the car into neutral and turn it off and back on again as well.

[soul_hfk]

lets start over with the shuttering when your braking is it normal braking or are u slamming them to the floor cause if its normal braking it would be warped rotors if your slamming them on then it is the ABS kicking in

[bobby1]

For statrters, I did top up my brake fluid which solved my problem regarding the lights that were displaying- they are now OFF.- thanks
As far as the vibration goes, when I am braking normally (no slamming), even at a very low speed when I approach a stop sign the front end starts to shutter. Kep in mind, this happens once in a while - not all the time. I called Infiniti yesterday and they advised me that based in my VIN#, there was no recall for the vehicle rearding the brakes. Thanks for the the reposnse, but I am curious how I would get warped rotors if that indeed is the problme. thanks

[soul_hfk]

well when the rotors get really hot they warp i would buy new rotors the next time you need brake pads but if you can do it yourself you can save some money

i really like using stillens stuff heres the link
http://www.stillen.com/browse.asp?c=BR& ... model=QX56

[C-Kwik]

lets start over with the shuttering when your braking is it normal braking or are u slamming them to the floor cause if its normal braking it would be warped rotors if your slamming them on then it is the ABS kicking in

Not necessarily. There is a very specific problem that occurs with some Titans, Armadas and QX56. The system somehow malfunctions and goes into a failsafe type of mode where the ABS is constantly in ready state. Each time you hit the brakes, the ABS engages. There is a TSB for it. If the ABS system were working properly, then you are correct, but what he is describing sounds a lot like the problem described in the TSB, which is also a problem I've experienced firsthand.

To better describe this problem, if you feel light and fairly high frequency vibrations in the pedal along with odd pedal modulation, then its likely the problem I described. The ABS and VDC lights will turn on when the ABS system goes into this ready mode. Sometimes, you might catch the lights turn on before you feel it in the pedal.

A rotor warpage scenario will most likely be felt primarily in the steering wheel whose vibration varies with speed. If its a warpage issue, you'll likely need to change the rotors. Rotors rarely actually warp anymore. More common is the formation of cementite from resting a brake pad against a hot rotor for too long. The build-up of cementite will cause uneven wear at different areas of the rotor causing a high and low spot similar to a warped rotor. The difference is, such a rotor with cementite embedded in it will end up in the same condition after turning the rotor. Whereas a warped rotor can be turned so long as there is enough material left.

[soul_hfk]

not really "rarely" had a 07 G35x and had to replace them in the 2nd yr i had her and im driving a 08ex cause the QX is a sitting at the dealer and its doing it to

[C-Kwik]

http://stoptech.com/tech_info/wp_warped_brakedisk.shtml

Stillen's brake guys say pretty much the same thing.

The symptoms are pretty much identical to warped rotors. But its not an actual warping of the rotor that occurs but a thickness variance as a result of uneven wear at different points along the rotor surface. While it seems trivial to discern a difference, its important to understand the difference and what the actual cause of the problem is so the proper remedy can be applied.

[soul_hfk]

i havent pulled the tires on the EX cause its not my car but i know on my G they where warped cause i took it to the dealer to try to get them to replace them and they told me that they where not covered but they where warped then told me it was how i drive anyways warped or uneven in the end only way to fix is to cut them down or replace them rite

[bobby1]

thanks to everyone, I had my rotors replaced and everything is back to normal working condition.Cheers.

[soul_hfk]

anytime. that what the forums are here for

[soul_hfk]

oh any pics?

[tcoleman]

Bobby1; Just bought a 2004 QX56 144k miles and the owner said the pads were replaced but not the rotors. I had the same thing happen to me the day I bought it (yesterday), and the brake light came on and the car shook moderately when slowing down-not slamming. Did you replace your front two rotors and this fixed the problem? Thanks in advance.