I have noticed a very severe brake shudder at +70 mph.https://www.gmforum.com/images/smilies/confused.gif

Just less than a year ago I put on the R1 Concepts drilled and slotted rotors, front and back. I'm thinking that the rotors, (probably front): are warping or possibly the tires are out of balance. Any thoughts on the best way to check and resolve this issue?

Try getting the tires balanced and if that don't correct the issue then it has to the the rotors.........

Please describe brake shudder. Are the brakes pulsating very rapidly when you hit the brake, or is it just a vibration while cruising?

If it is a vibration while cruising, a tire balance will be your #1 bet. After that, check your wheel hubs and tie rods. Those two like to go and the factory tie rods are complete garbage. I've dealt with front end vibrations on my Bonneville more than you can imagine, and the R1 rotors I have on there now have taken a lot of abuse yet still aren't warped after 40k+ miles.

In my case the Brakes pulsate rapidly when you hit the brake. I had the tires rotated and balanced yesterday, took it out and still the brakes shudder. I checked the wheel bearings last night and they seem nice and tight. I was starting to look for a dial gauge so I could check the run out. What is the best way to check the tie rods on a Bonnnie?

At higher speeds I can really hear and feel the shudder and at lower speeds you kind of get the sense of a very slight pulse.

Best way to check the tie rods is to jack up the front of the car, leave the column unlocked. Grab the wheel at 9 and 3 oclock and shake side to side. If you feel any play, replace them. Make sure the play is in the outer before you replace them, sometimes its hard to tell the inner from the outer when its really slight.

When I checked the wheel bearing I also did check the 9-3 play and there is quite a bit of play but didn't know what the 9-3 play meant. Will take a look tonight and see if it is the inner or outer.

I was considering some suspension work on the front. Such as replacing struts and bushings for the sway bar but I'm not sure if I want to do tie rods and it all at once.

If you're on the factory tie rods, those things are **terrible**. They are literally 1/3 the weight of the Moog parts I put on to replace them.

apply the parking brake slightly and see if it shudders,,,,,,,,, if yes,,,, rears,,,,,, p.*. My R1'* warped already to,,,, a lil pissed about it !!!

How in the world are you guys warping your rotors? I overheated my brakes to the point of complete failure and they aren't yet warped, going on 40k miles now.

Have you actually replaced your rotors to verify that they were indeed warped and it wasn't something else? How long have you had them?

going on 2 years,,,,,, I think these are undersized for our cars IMHO

Replace all 4 corners at one time,,,, been warped for a few moths now,,,, will be replacing again soon.

P.*. I live in New Lenox as well