Brake shudder

Hey, in process of putting my 98 2.7l 2WD 4runner back on the road.
I get a brake shudder when braking over like 45MPH.
Replaced and had trust worthy mechanic (but not a Toyota specialist) look at it and it still does it before and after all the stuff I am about to list was done.
New master cylinder, new rotors, pads, new drums and shoes, new tires, new steering rack bushings, and alignment. It does it less than before I replaced all these items. Could it be a break in period for new brakes? Haven't even put 50 miles on yet since work was done.
Alignment shop found nothing in front worn and I also do not.

Could it be the ABS? anything else I can look into? I have googled and researched this but everything points to warped rotors but I find that hard to believe since it did it before and after rotor replacement.

 

My guess would be warped rotors but then you're staying the rotors are new. Did you use these Toyota rotors or not? I have not had good luck with non-OEM rotors and eventually switched back to Toyota. To be more specific, every time that I replaced my front rotors with non-OEM rotors, it did not take long before they warped. Along the way I also switched back to Toyota brake pads.

 

Rotors are the first thing that come to mind. Did it start immediately after they were replaced, or did it take a little driving before the shudder started?

 

Did you spray brake cleaner on the new rotors and clean before install?
Must be air in the line try bleeding again, two person manually?

 

Did you use shims on the brake pads?

 

Try to loosen the lug nuts and re-torque them with a torque wrench.

I've had rotors go to shit quick because some lube tech thought it was ok to go to town with an impact.

I know you said trusted mechanic but Ive seen seasoned mechanics use impacts.

 

I have replaced rotors, brake pads, looked at wheels and tires. All are top notch and working. When ABS is working, all works smoothly, for some reason the ABS will inadvertantly turn off and I get an extreme shudder when braking at higher speeds and brakes can lock up. When ABS is working, all is fine and no shudder, and braking is as smooth as can be. Any information on ABS system and why it would inadvertently turn on and then off? Very frustrated!!!

Note, Wilwood Calipers and Slotted and drilled discs added. Rear brakes and Emergency Brake replaced in the last month.

 

Have you checked the ABS sensors?

 

I went through a local car wash, corolla, brakes squeaked a little afterwards i think they use recycled water? My 4R brakes smooth and fast. Even has progressive brakeing. I would bleed the system one more time?

 

fox744, I have not checked the sensors. Actually I do not know where to start or what they look like. Could you provide more information?

 

SR5 Limited, we are not talking about squeaking, no disrespect, but I am trying to address a very distinct shudder that affects the stopping capability.

 

With all due respect Timmy the Toolman, Brake Shudder has to do with the ABS system, nothing to do with torquing lug nuts...

 

You know Timmy, I've been driving for 47 years. I was a mechanic for 10 of those years and did hundreds of break jobs. I think I've got a pretty good idea of how the ABS works.

 

I’ll throw in my two cents. Brake rotors almost never warp. An improperly seated wheel or rotor as Timmy mentioned is far more likely than warp.

 

When is the last time you had your wheels balanced?