Well, took the RX300 in to the Lexus dealer yestarday and they replaced the pads and turned the rotors and - WOW - smooth as a baby's backside now!!! No vibration or shuddering. The symptoms of worn rotors are shuddering when lightly applying the brakes at speed (50-60mph). I have a BMW and they are notorious for shimmys when the bushings get worn but that's usually shimmying all the time (may be worse on braking). In this instance, though, rotors appear to be the most likely culprit.

 

You are not the one with the original problem
Was the steering wheel shuddering or the whole car was jerking on high speeds when lightly applying brakes? Let us see how dfish solves his problem.
I also found this, this , and this -- 50% of people saying it is rotors, others dare rod tod ends.

 

Meetya. U r only one sayings it the rod ends. Everyone else is saying rotors. How is that 50%. Majority of the time if your car only shakes voilently when appling brakes only, its the rotors.

 

Rod ends can get loose and need replacing, sometimes it is just a tiny bit, but is easily felt through the steering wheel. But, before replacing this make sure it is not some other part of the suspension.

 

Thanks for all the suggestions. I'll get it checked out by a local mechanic and I'll ask him about the differing diagnoses.

Its definitely a fast shuddering of the steering wheel only when braking at high speed. the whole chassis doesnt shudder.

low speed braking issues feels like rim braking on a bike when the wheel isnt true. the cyclical swing in braking power leads me to believe the rotor is warped.

once the mechanic lets me know whats wrong ill order the parts and get it installed.

 

Check this out: https://www.clublexus.com/forums/sho...d.php?t=284148

 

Just get a local brake shop to turn your rotors and repace pads if necessary. Your problem will be gone. Another alternative is replacement rotors and DIY as suggested above. Either way , your problem will be solved.

 

Just had the 90k service and brake inspection.
The rotors are warped.

$240 to change all brake pads and re surface all motors.

Mechanic recommended waiting 5k more since there still some life left in the pads before doing the brake job.

 

Machining rotors is easy. My uncle is getting a machine that can do this instead of taking it down the street to do all 4 rotors for about $25 USD total.

 

Turning rotors are $8 each at autozone or any mechanics shop that does brakes.