Pulsating Brake pedal. HELP!

[jbres]

I have a 2003 Tahoe. About 30,000 miles ago, I replaced front brake pads and rotors, and rear pads only. NOW, I am getting some SLIGHT pulsating when applying the brakes gently. When applying them hard, don't really feel anything.
I have no ABS light on, and when I visually look at my rear rotors they do have some "grooves" or "streaks" going through them. They are not in perfect flush shape.
Is my rear rotors the problem?
Thanks!

[dapperdan]

Had almost the same thing happen years ago on one of my pickups, warped rotor for sure. I doubt you'll be able to have it turned, although you can try. Most shops are going to try and sell you new rotors. Just say'n

Dan

[jbres]

yes there is a rust ridge, as I can visually see. Also, I forgot to mention, I do here some "noise" out of the rear tire each time the rear wheel rotates. (I can hear it when the Tahoe is coming up the driveway, as I wasn't sure where the noise is even coming from, as its not a squealing noise.)
I will jack it up this weekend and check it all out.

[dodge_guy]

Double check the rear rotors. is there a rust ridge? if there is there could be a chunk of rust missing causing the pad to hit the low rust spot causing the pulsation!

Good luck!

[Lynnmor]

If it started with the new front rotors, then they are likely the problem. That said, I had a Tahoe with a similar problem. To make a real long story short, it turned out to be the rear rotors where the parking brake shoes contact the drum surface. They were way out of round from the factory and I had to show Mr. Goodwrench the problem as he couldn't find it.

[kaz442]

I have had new rotors be warped out of the box.Did a broke job on my van could feel the warped rotor when braking. Jacked up each wheel and spun tire slowly and could here the rotor scrape the brake pad every so often. Change only the one warped rotor and all was good.

[BurbMan]

Turtle n Peeps wrote:
The junk I've seen come out of parts houses now days I would wager the "new" front stuff is warped.

Bingo. Rotors don't really "warp" but they can heat unevenly resulting in uneven deposits of pad material that create high spots on the rotors, and that';s what creates the pulsating effect when you apply the brakes.

In a safe area try a 2-3 real hard panic stops. Don't come to a complete stop at the end, but take your foot off the brake and re-accelerate. After the 3rd one drive around for a few minutes until the rotors cool down before applying the brakes again. Sometimes this helps even out the deposits of pad material on the rotors.

[Turtle_n_Peeps]

The junk I've seen come out of parts houses now days I would wager the "new" front stuff is warped.

[jbres]

terryallan- how do you have them turned? Would it be cheaper to just buy new?

[Terryallan]

Sounds like you have at least one warped rotor. Could be the rear. Have them turned and see if it stops it. Won't take long.