Bandit 00C5

Well finally having enough of the front end shakes, tonight I installed new GM performance rotors and new pads. I have done enough brake jobs in my life to know that a pulsing brake pedal is usually a sure sign of warped rotors. After I did the install tonight I seated the pads like I have done many many times. Drove the car for a short bit and noticed right away the I still have front end shake and the pulsing pedal. It is not nearly as bad as it was but still far more than it should be. Anybody encountered this or have a clue what might be my culprit??? I checked the tie rods ends and there is a small amount of play but I dont think enough to cause this. I did not do the rears and wonder if the rears could be warped bad enough to be transmitting up through the brake system. Ive got 150,000 so maybe Ive got several issues to address.

81c3

With those miles, Id definitely look at the rears. Might as well just did all 4 wheels at the same time.

Bandit 00C5

The rears were done when I last did brakes. Installed new pads and rotors on all four corners. I figured with the way I drive I just used up the fronts. Drove to work this morning and the slightest touch of the pedal and the pulsing sensation gets pretty bad. I just having a hard time believing that the rears could be causing this. I have new rears also and will change them this weekend and see if that resolves it.

striper

Being around new car dealers in my work, I've seen several times where mechanics haven taken warped new rotors right out of the box. IMHO, maybe you should try aftermarket rotors where they are built on smaller production runs. OEM rotors are probably built by the thousands at a time, and not necessarily out of the best materials. Brakemotive.com as outrageous deals on rotors and pads. I've used them and they are fantastic for the price.

ztheusa

Some new rotors come warped right out of the box. Some brake shops require that new rotors be machined.

dankhts

check the tie rod ends?

CHJ In Virginia

Do your self a favor and go to one of the local parts stores and rent a runout dial indicator. Take measurements FRONT AND BACK on every rotor. Without looking it up, the GM spec is 3 to 4 / 1000 max runout. That way you will know for sure if you have a warped rotor or another suspension problem causing the pulsation. $10 spent on the dial indicator rental is much better than just throwing parts at the car and hoping for a fix.

Frank4202

Is it possible you might have a warped hub? Possible the hub is warped so the rotor is not sitting flush.

AU N EGL

Nope

Bent calipers. Time for new calipers

SaberD

there shouldnt be any play when checking your tie rod ends or wheel bearings.

Bill Dearborn

Have you made sure the wheels are on properly? When you reinstalled the wheel did you make sure it sat flush against the rotor and the rotor flush against the hub face? All it takes is a little corrosion or a burr on the hub to prevent proper seating and you get the thumping. Have seen it on a lot of vehicles.

Bill

81c3

I am not familiar with this being an issue. Please explain.

SG Lou

Bent calipers ? That's a new one on me

AU N EGL

Called Caliper Spread.

If your old brake pads are beveled, not worn evenly from one end to the other, chances are the caliper is bent.

Measure the distance on each side of the caliper where the brake pad fits in. Should be the same distance.

Those of us that beat the living chit out of our cars on the race track / track days, know about caliper spread

I toss and replace my front brake calipers each winter.


And yes Tie Rod ends need to be replaced occasionally

and wheel bearings do go bad. When a wheel bearing is replaced do each side, both front or both rear bearings

Good Luck

irloyal

How are your tires? If you have a severe tire issue it will mimick a warped rotor because it will start to shake so bad even at low speeds. It could be a thrown wheel weight, or badly worn (uneven) or chunked tire, or it could be an internal ply problem that is throwing the tire out of balance. I had a front set of tires that had a ply starting to seperate on the inside, and it felt just like a warped rotor as soon as I reached about 20 mph.

johnson-rod

Two things you can check - both sound strange but have worked for me.

Lug nut torque. Use a torque wrench and tighten all the nuts in a star pattern to the factory setting (100ft/lbs I think) This has eliminated brake pulsating in several of my cars. Give it a few days to take effect.

Break in your new pads and rotors or clean your old ones. Do several hard stops from 60 or 70 mph down to 10 or 15 mph. Repeat several times. It cleans the rotors and the pads. I have to do this occasionally with my C5 or I get bad pulsing. I'm usually very gentle with my brakes and I don't think they appreciate it. Mine are original pads and rotors with 100K miles.

Neither costs anything and has worked for me.

Dope

If you say you get a vibration and pedal pulsation ONLY when hitting the brakes, and you've replaced the front brakes, it's pretty clear what your next step is. Replace the rears and I bet it will be fine.

I've had vibration caused by rear brakes on two different vehicles in the past, it's not hard to believe. In both cases they were FWD cars with undersized/unvented rear rotors but it happens.

Something like a bad hub or tie rods or whatever would give you problems all of the time. Vibration under braking == almost certainly rotors. What else could it realistically be?

Dope

Bandit 00C5

WINNER!!! Update, replaced the rears last night and now all is good. Feels so much better to drive. For all of those that offered advice I say Thank You. If the rotors had not fixed it I was going to start following some of the other suggestions given. Can't beat the knowledge and wit of CF.

81c3

Winner? Really? Check post #2.

Bandit 00C5

AHHHH....your absolutely right. When I did the fronts I just didn't have the time to do the rears too. To you I say Thanks and am glad to just not have more severe problems.