I thought what I had was a classic case of rear warped rotors. When braking above 40mph car shakes, the higher the speed the more it shakes upon braking. It only shakes when braking, steering wheel does not shake. I have plenty of pads left in the rear so I went put on new rotors only. Unfortunately the car does the same thing, I'm assuming it has to do something with the brakes because it only happens when brakes are applied. I have a 06 g35 AT (not brembo) and the caliper bolts, slide in pins, and wheel lugs are all torqued to spec. .

Thanks in Advance!

 

You screwed up doing rotors only. You replace pads and rotors as a unit, buy pads, take the rotors off and get them resurfaced (can't just re-use them as is sorry, pads have already done the damage).

Chances are the FRONT rotors are where the issue is since the fronts do 80% of the braking for the entire vehicle, buy rotors and pads for them as well.

Don't forget to follow proper "bed-in" procedure for the pads or you might as well just throw your $100 in the garbage can.

 

I would think if front rotors were causing issue I would feel it in my steering wheel, no? My front pads are pretty worn 4mm left and I already have replacement pads ready to install. I don't mind getting new rotors for the fronts too. I guess then the question is should I go ahead and get new rear pads as well and resurface the new rears or if the problem really is just the front rotors then wouldn't replacing front pads and rotors do the trick?

 

Firstly I would correct the brake shudder and since the fronts haven't been touched I would do those properly to eliminate that as the problem. Usually if the problem is the rotors you can feel the pulses quicken and slow as the vehicle speed goes up/down. You will not feel it in the steering wheel unless you have worn steering component or the vibration/warpage is SUBSTANTIAL and literally shaking the entire vehicle. A warped rotor does not cause the steering to actually TURN necessarily and there is pretty sufficient dampening after you account for the rack and pinion.

Typically it's felt along the entire chassis and almost impossible to tell which specific end it's coming from until you have it buckled down on a Dyno to eliminate the front wheels turning.

You can mic out the rotor with a dial caliper to check it for yourself. The more rudimentary method of using a straight edge rule is an option too if it's substantially warped.

Don't bother getting a warped rotor resurfaced, if it's been exposed to the level of heat needed to warp the metal it's better off in the recycle bin.

 

If you have shudder/shaking when applying the brakes it's a good idea to replace all four rotors and pads to eliminate this issue. Do you realize the issues of warped rotors is caused by tire installers using an impact gun doing install, something you should never allow! Torque figures for your wheel lugs are 80 psi...Gary

 

The rear wheels are torqued to 80 ft-lb as I just put on the rotors yesterday and torqued them myself. However after reading this I checked the front and a few lugs were torqued to probably 160, went ahead and re torqued them back to 80. I'm waiting for the front rotors to arrive to do the front pads and rotors. Hopefully that does the trick.

 

80 PSI!!!! lol

 

Yep 80 PSI

I hate dipshits at tires stores using air ratchets to pretorque lug nuts, it's too hard on everything, the stud, the nut, the wheel, the rotor, everything. 160 ft/lbs is enough to break the stud, damage the thread, etc. Watch them like a hawk and when your vehicle is about to get it's wheels back on go STAND NEXT TO YOUR CAR AND WATCH because it's your *** on the highway when something breaks...

 

I'm happy to report that replacing the front rotors and pads did the trick. I may have replaced the rear rotors for no reason, but at almost 130K miles it was probably time (I want to say they were resurfaced 2 or 3 times in the past).

 

That was twice more than they should have been surfaced! Doesn't anyone check the specs on turned rotors anymore? Glad you have your issue solved, remember no impact guns ever while installing wheels!
Gary