I just passed 50K miles on my Z and the brakes have started pulsating. The dealer (service writer) said the mechanic "looked" at the brakes and they were fine. When I suggested he actually drive the car he called me back and said; "Oh yes, they did feel the pulsation. The rotors need to be turned." Arrgh... This will be my third set of rotors in only 50K miles. I got the usual, "well you know it depends on your driving style...." crap.
My question to you all is this: I have never run the car on the track and never locked up the brakes. Of course I have done some "spirited" driving but nothing outrageous in my mind. Do you think it is normal to be replacing rotors at this pace? I have heard that overtorquing the lug nuts can cause problems. The pads have plenty of meat on them and are not glazed. Any suggestions other than find a mechanic that knows (or cares) what the hell he is talking about?
Thanks in advance!

 

What rotors were put on? I'm assuming they aren't cross dilled or slotted?

 

Uneven torquing / over torquing of lug bolts can cause this problem. No I don't think it's normal to go through 3 sets of rotors in 50K miles. Were the replacements stock GM Z rotors or aftermarket? Check the torque on those lugs before you do anything else. I'm on original rotors after 6 years and 40K miles on my Z51 brakes. I always hand torque the lugs whenever I remove & reinstall a wheel. Impact wrenches can be disastrous.

 

If you get the brakes hot in spirited street driving, then come to a stop and hold your foot on the brake pedal; some pad material can transfer to the rotors and give the pulsation like the rotor is warped.

IIRC, sanding the face of the rotors can fix this up, turning them would do it also but more complicated.

Brakes experts should be along soon...

 

I've heard the same thing. After the car is stopped, take your foot off the brake. Automatic?

 

NOT a brake expert, but if you go to either stoptech or some other brake pad/caliper/rotor sites, you'll find some tech papers there. Some of them state that there's actually not as many "warped rotors" as there are transfer material "spots" which, as said above can be taken off with light sanding.

Like light squeaking/squealing, there is another method for pulsation which I tend to try first. I find a nice road where there's no one on it, and I get up to 40 or more and hit the brakes hard, not lockup, but hard. Sometimes, a few times. Works most of the time. Try the easiest (and sometimes least costly) things first.

 

Said it's a Z so no automatic.

 

I have an '05 F55 C6, and I got approximately 100K miles on the original rotors. I currently have a set of used stock rotors with about 45K miles on them. No pulsing issues at all on either set of rotors.

How the lug nots are tightened can have a HUGE impact on pulsing brakes. If you watch how "most" dealership tech's tighten lug nuts you'd be livid.

The proper technique is to tighten the lug nots in 2-3 passes and always, always in a star pattern. What most tech's do is use an impact gun and tighten to full torque in on pass, while just going around the wheel (not a cross/star pattern). This is almost guaranteed to result in pulsating brakes.

Whenever, I cannot avoid having someone else put wheels on my car, the first thing a do when I get home is to loosen the lug nuts and re-tighten then by hand myself.

As was also mentioned, a lot of pulsating brakes is also caused by uneven pad material transference to the rotor surface. This can be "mostly" corrected by sanding or turning the rotors.

It can also be reduced by re-seating the pads as was noted above.

I also think that washing a car and then letting it sit for a long period of time without getting ALL the water/moisture off the rotors/pads can cause problems as the pads will freeze/rust to the rotor surface. I have had this happen many times with the car sitting for only 1-2 days. Re-seating the pads should diminish this problem, but may not eliminate it entirely.

 

I tend to agree with the mechanic. Read the Stop Tech White paper about the warped rotor myth http://www.stoptech.com/technical-su...nd-other-myths.

Read the paper and see what causes the thumping and then think about how you drive and use the brakes. Get the rotors turned and then take corrective action. Realize the turned rotors will be more susceptible to the problem since they are somewhat thinner thus have reduced mass and heat up faster.

Bill

 

As said; Proper torque is a must for a large rotor. Turning a tweaked rotor is useless. If you drive to local car wash let the rotors cool before hitting them with cold water. Rust is common due to the high carbon content of the steel, and last some people are two footers, one foot on the gas and one foot on the brake. I see it all the time, and they wonder why they are pissing through pads and rotors.

 

OP: If you do end up replaceing your rotors, take a look at these - http://shop.performanceafx.com/C6-Z06_c14.htm I have a set of the slotted ones on my 07.

 

Douglas in Green Bay

 

Stock Z06 rotors from the dealer.....if I am to trust the dealer...

 

Thanks for the input guys! From what you have said and what I have been able to read on the net I think I will scrub the rotors and retorque the lug nuts. Think I will do my own brake work from now on. I was just scared of the 6 puck fronts but from watching YouTube it looks as easy as "normal" brakes.

Happy driving all.

 

I bought my rotors and ceramic pads from brake motive about 1.5 years ago and it all looks like new still. I think it was about $375 or so for everything and they are zink coated

 

I have been fighting this problem ever since I installed ceramic pads. 20,000 miles of pure agrivation trying to solve the problem. The brake experts are correct about the pad material, thin turned rotors, and driving style specific pads. My solution finally arrived via Spring Mountain Motorsports technical advice in that they use Hawk Brake Pads, HPS, only. I do not drive on the track but I drag race, open road events, standing mole events (Mojave Mile) and do my own tuning. The ceramic pads worked great if you are slowing down from normal cruise speeds, but the mimute you touch the brakes at the top of 4th (162) or better, to avoid being "Captured" while tuning, say goodby to smooth stops and eventually you will get vibration at normal highway speeds. I am living proof that pad material builds up on the rotors as stated above and that the rotors will get the "Measels" blue spots like on the flywheel face, if you use ceramics on stock rotors. Give yourself a break and follow my advice. Turn the rotors and install the Hawk HPS(High Performance Street) pads.

 

nice looking rotors

 

Every time I have had rotors turned I end up with same issue....I quit having the rotors turned and sucked up the cost of new rotors when in need and haven't had the problem since.