Hi gang -

Got my CPO 2016 in June, came with new rotors and pads. Have driven about 1k miles and I’m noticing some shudder/judder at initial light brake pressure when traveling at 35mph or above. In fact, the brakes in general feel pretty bad, very stiff and not smooth or grabby at all.

I am just now noticing this so open to thoughts. I had spacers installed about 300 miles ago but everything is smooth there, no vibrations at speed or issues. Problem only happens when braking.

Saw a separate post about new rotors or pads not being broken in properly and needing tech stream treatment or something? Also, lug nuts not being torques properly can cause?

I plan on taking to dealer soon to have them assess. Thanks everyone.

 

If you have spacers you need to take off the wheels and check the torque on all of the lugnuts for your spacers. I believe factory torque specs are 80ft/lbs. Make sure the spacers are hubcentric. If all checks out then reinstall your wheels and do the same thing. Take it for a test drive. IF that doesn't solve your problem, what do you mean by shudder? Does it sound or feel like you have a high spot on a rotor and you're getting feed back through the steering wheel? That could possibly be pad imprinting, which is caused by getting the brakes excessively hot and not allowing them to cool down before you depress the brake pedal to keep the car from moving and leave it pressed in for an extended period of time. If the pads and rotors are very, very hot and one does this, it leaves deposits or "imprints" from the pads onto the rotors and it's nearly impossible to get rid of it once that happens.


Steve

 

Steve, this is very helpful. I don’t think it’s brakes overheating , I don’t drive high speed or ‘hardcore’ enough to heat up the rotors at an extreme temperature that you’re suggesting...I do low speed commute to work and periodic normal highway driving.

I had a performance shop install the spacers, so I think it’s more likely (even if unlikely?) they did not torque to exact Lexus spec , which you are correct, is 80 ft lbs. I suppose I can have them check, or have the dealer check?

 

Did you notice the brake shudder before the spacers install?

 

I did not. And I did not notice anything for about 2 months after the spacers were installed. Would improperly torques nuts take a little while to manifest, I suppose? It sounds like that’s the first thing I should check, I actually found this technical bulletin from Lexus specifically highlighting the importance of torquing nuts to spec.

ttps://static.nhtsa.gov/odi/tsbs/2016/MC-10132888-9999.pdf

 

usually brake shudder is an indication of a warped rotors. i don't think it is the lug nuts from the spacers, because if it is the lug nuts, they will cause a balance issue (a vibration while driving during or above a certain speed) and not a shudder while braking. maybe the spacers caused the warped rotors. i would have the rotors checked first. keep in mind that our rotors can't be resurfaced if warped if i'm not mistaken.

 

Rotors don't warp unless you do something really dumb. They get deposits on them that make the brakes feel warped, but they're not. Normally this means new rotors because the deposits aren't easy to remove and often have formed cementite, so the rotors are junk. If this only happens while braking lightly, you should try bedding the pads first, and if that doesn't work, replace the pads with something of known quality. Not all pads are going to work well, and ceramic pads are the most likely to present issues if they're not broken in properly. I chased a bad pedal in the wife's Scion tC for more than a year thinking there was air in the brake lines, when the real issue was the pads were garbage. They stopped the car, but the feel was horrible.

 

Agree with Lobux regarding the rotors being warped. It’s really hard to do that on the street. Pad imprinting is another story though. I would pull the wheels and look at the spacer lug nuts. Also, what brand spacer? The H&R seem to be the only reputable ones as others have had issues. If you aren’t mechanically inclined enough to check them on your own I’d take them in right away. This isn’t something you want to wait on.

Steve

 

Lexus service called me today and said my front rotors are indeed warped. Advisor said he sees this sometimes and it not unheard of...manufacturing defect with the way they are cast, etc. Thoughts? Are brakes an ‘issue’ with Lexus? I had the same Brembo system on my previous C63 AMGs, never had any issues....

 

no they are not, i had 4 different lexus cars in the last 15 years and never had issues with brakes, but as your advisor said, it does happen sometimes due to certain circumstances or defects.

 

Brakes at the dealer stories are far too many to believe this is true. I've heard of service departments recommending pad replacement with 5mm of pad left - that's barely 50% worn. Warped? Seriously doubt that.

 

Hate to say it, but that's a nice bill for them and something they can change in literally 15 mins per side. If you end up getting new rotors be sure to "bed" them in properly. There are instructions on the web that explain how to do it. Make sure you do it early in the morning or really late at night so there is less traffic.

These Brembos on the Lexus and many other performance cars don't have rotor issues.

Steve

 

Likely causes:
1. Improper bedding.
2. Incorrect/uneven lug nut torque. Dealers and wheel shops are notorious for using an impact gun and/or not hand torquing wheels in a "star pattern".
3. The Brembo wheels and pads are bullett proof. I have a 2016 with 31K miles on the original pads and rotors (street driving only, no track). I always manually retorque the wheels in star pattern anytime the wheels are removed.

 

Also the rotors are not "warped" but instead have uneven brake pad material deposition causes vibration on braking.