Vibration while braking

[Rannos]

I recently bought a 2005 silverado ext cab with the lq9 6.0. Truck has about 55k miles on it now and has an intermittent vibration while braking. It did this when I drove the truck at the dealer and they turned the rotors and installed fresh pads. When I came back to pick it up it seemed like it was cleared up but now its intermittent. I can drive all day and it may only do it once or twice or it may do it almost every time I stop on my way to work (25miles). I pulled a front wheel off and spun the rotor with an indicator on it looks good. Recently it has started to get worse and seems like it starts up front and the vibrations travels to the rear of the truck. I have no idea what could cause this. If anyone has had a similar problem and can point me in the right direction I would be grateful.

[HTX86chevy]

My guess would be to check the wheel bearings first. Get the tires balanced also. If this doesnt work , then i am almost certain that the rotors are no good. Even if they were turned already.

[Mike Bradbury]

Had this trouble on my Explorer and had the rotors turned and it worked for 10,000 mi then started again. finally just had them replaced. Now it has 200,000 on it and they vibrate only when comming off the freeway at higher speeds. I think the rotors might be a softer alloy.

[Rannos]

When I had the wheel off I checked the bearings on that side for brinelling and found none. The bearing don't have the dis-colored appearance of over heating or the rough spots associated with contamination, fatigue or corrosion failures. So I have to assume they are good... may change them anyway this weekend to be sure. Also with it being intermittent I have a hard time believing it's the wheel bearings or rotors, but I could be mistaken. Like I said in my earlier post I can drive all day and it may not do it at all, But I have also had it do it the first time I pull out of my driveway, so I don't it is a heat related issue either. As for the tires I already had the balance checked and they were balanced correctly and they are brand new tires... well they have about 5k miles on them now. I was told by the owner of the tire shop that he has seen similar [problems and it be related to ABS and the speed sensor but that when that occurs the ABS light should flash but it does not. He also mentioned the front brake lines maybe getting soft. Never heard of this but he has numerous of these year model trucks for work and has one he takes to the track and seems like he is informed on them. Anyone heard of the brake lines causing this type of issue?

[k5hart]

My 2006 that I just got seems to do this also but not that bad. Usually stopping at high speed. I just figure it's the rotors. I had an HHR that did this terribly from new until I put on aftermarket rotors. One interesting note about that, I put high performance pads on at the same time and I still had some vibration. I pulled just the pad and put the stock ones back on and it was perfect.

[Scooterr]

Sounds like warped rotors, mine are bad, its just finding the money to replace them right now.
If I was you Id take them somewhere and have them checked

[iluvmy72]

check alignment and ball joints

[HTX86chevy]

if its the abs acting up you can easily disconnect the harness that is in the wheel wells and see if it gets better. mine acts up also so i have the driver side disconnected. when it was acting up the light never came on. when your rotors were removed to have them turned, the speed sensor could have gotten dirty and it may not read correctly causing this problem