Brake Vibration Question????

[MoonshineXXX]

Hey Guys,

I had new rotors installed on the wife's 2009 Denali XL today and after her shake down run coming down a step incline on a local highway, she informed me that the vibration was better but still there. There was little to no vibration in normal driving around town and on relatively flat highway, but we live in western NC, so there are some steep grades that we frequent as well. I drove the truck this afternoon and it felt fine, just like before, but I've driven the truck down the same road she was on today and felt quite a bit of vibration myself, which prompted me to purchase the new rotors. And since the fronts do most of the work I just assumed they were the culprits.

All this being stated, should I change the rear rotors also? And what about the pads? Could they be suspect as well? My mechanic didn't say anything about the pads, so I assume they are well within spec. Any advice/suggestions will be greatly appreciated!

 

[Gzes]

You sure the road doesnt just have alot of vibration? If not rotors could be slightly warped but doubt it. Its the road imo

 

[quattrotman]

You sure the road doesnt just have alot of vibration? If not rotors could be slightly warped but doubt it. Its the road imo

I frequent a stretch of highway that makes my wheels feel out of balance but it's the road. That may produce your symptom. Is the steering wheel shaking or do you feel it in your butt. The steering wheel indicates front rotors and butt vibrations indicate rear rotors. There is also the strong possibility that your ball joints are worn. This can cause vibrations even just when braking.

 

[02Lightning]

Hey Guys,

And what about the pads? Could they be suspect as well?

Sand down your pads to get some of the glaze off of them, so they will seat into the new rotors. Or just buy new pads. Pads won't make a car pulsate.

 

[MoonshineXXX]

UPDATE - The tires were rotated at the same time the new rotors were installed, and the truck had more vibration than before around 70mph. So I had the front tires checked and found that they were out of balance. I guess them being in the rear masked that a bit... Anyway they are balanced now. Now the truck drives well at speed but per the wife, the pulsation is still evident when braking on the same stretch of road with the steep grade. The pads were verified to be in great shape at the time of the front tire balance, so this makes me think the rear rotors need to be replaced as well since the vibration got better after the new rotors were installed and the truck doesn't vibrate under braking on lesser grade. She said the truck vibrates all over and not just in the steering wheel when it does vibrate, so that makes me think the rear rotors could be culprit. With all that being stated, I'll be ordering some rear rotors this afternoon...

And probably a new set of tires soon too... Which will open up a whole new bag of worms!