ravenuer

The OP said it only vibrates when he steps on the brakes, so to me that means it's not a balance issue.

Jjjmpp1953

Purchased a CPO 2018 RX350 with 27K. Took trip to Vegas a month later and noticed significant vibrating/wobbling in steering wheel going downhill above 70 mph with cruise control auto braking. Took in to Lexus and they said it was my wife’s hard braking. They checked pads and had less than 5% wear but still insisted a wear and tear issue. Told my wife to turn off cruise control while going downhill and to down shift to slow down instead of braking! I got on phone and asked where does say that in owners manual? Took trip to Monterey from Oceanside a month later and AGAIN had same issue but worse. Took back in to Lexus at 3k more and they said it is NOT covered but if we wanted to pay $900 to have rotors turned they would be happy to do it. Sent email to South County Lexus in response to survey and asked that they respond…crickets! Talked to certified Toyo mechanic and he said it is a well known problem that rotors warp due to overheating especially on downhill grades above 65 mph. This is our 5th Lexus and had similar issues with my LS 460. Every 6-9 months had to take her in to get rotors turned or replaced. The wobbling caused wear and stress on my ball joints and cost $2k to replace upper/lower and struts. Bottom line warped rotors are a well known problem due to a defective braking system and they refuse to fix it under warranty! IT IS NOT A WEAR AND TEAR ISSUE for the most part and Lexus should cover it but some dealers do and some don’t!

mikemu30

Unlikely the rotors are warped - most times when you experience the rumble during hard braking, it's uneven pad deposits that have accumulated on the rotors. I had that on my ES after about 20K miles - my solution was a few really hard braking episodes from high speed and voila - they've been silky smooth ever since. 42K miles now on the clock.

Cocal

The rotor warping is caused by 2 things, thinner rotors than they used to be (weight savings) and bad driving (braking) habits, one has to learn how to use the brakes for rotors nowadays can only be turned once if not too badly warped. please don't take it personally, yesterday's cars were a lot more forgiving than today's.

bamalam

I'm not trying to be argumentative, as this problem has been commonly reported and certainly is aggravating. The owner's guide, though, actually does say to use engine braking on long downhills. My 2020 guide says:

● Use engine braking (downshift) to maintain a safe speed when driving down a steep hill. Using the brakes continuously may cause the brakes to overheat and lose effectiveness. (P.180)

It also says that engine braking will not occur if dynamic radar cruise control with full speed range is activated, so disengaging cruise control is required.

autotech13

Unfortunately the rotors of today are not as thick as they used to be years ago. Everything today is made lighter and cheaper!

mikemu30

That's reason to NOT have the rotors turned!

mrmonster

What is "full speed range" because my adaptive cruise control always seems to use engine braking when attempting to slow down on bigger hills.

ravenuer

My first car with disc brakes was a 1970 Olds Cutlass. Put many, many miles on it with several brake jobs. Never had to machine or replace the rotors.

jjscsix

Sometimes the problem is brake pad material building up unevenly on the rotor. If so, a simple sanding that does not even get into the metal will fix it. I’ve done it myself.

mikemu30

That's the case most of the time. They rarely warp unless they've been cut once. A good hard braking from high speed can smooth things out as I said above.

RVAHoo

Drove the vehicle 12000 miles with no issues. First time I descended a moderate Blue Ridge hill and got the brakes hot, it started to pulsate. After cooling down, all was normal. I don’t think pad material on the rotor face is the cause. If it was, the hard braking would have cleaned it off. Conclusion is that heat temporarily warps the rotors.

mikemu30

Temporarily? Seems odd - the warping then magically disappears?

RVAHoo

It does seem odd. From past experience, once a brake pulsation condition arises, it’ll occur even during normal braking. I’ll just wait until pad replacement, and go with a quality aftermarket rotor. I’ve had good luck with Brembo blank rotors in the past.

mikemu30

I had a 73 Cutlass Supreme. Rocket engine, one of my favorite cars I ever owned. I felt special in those days because that car had FOUR SPEAKER stereo!!