RC F (2015-present) Discussion topics related to the RC F model

Carbotech 1521 problems. Unhappy buyer.

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Old 08-09-16, 02:07 PM
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rjmalm
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Default Carbotech 1521 problems. Unhappy buyer.

I decided to order Carbotech 1521 brakepads based on CL comments.

I had them installed by Lexus and had the rotors turned by Lexus a bit to make sure they had a good smooth match
and then I did the recommended bedding at Lexus before any freeway driving

Problems
1. The wear sensor cut out is WRONG. See pics. One can not use the wear sensor cable attachment. Lexus had to tie back the cables.
2. During the bedding process and later on my 5000 mile road trip I noticed that hard braking did not instill confidence like
the OEM pads or like the Project MU pads that I put on my IS-F. I did not test fade. They dont pull left or right but they just dont feel smooth.
3. I noticed that wear pattern on the rotors is not even. Lexus agreeds when I was at my 20k service yesterday. See pics.
4. Yes the dust is very low but I am not going to use these every again.
5. Carbotech would not compensate me for the incorrect sensor slots and I was told that Carbotech does not have the equipment to
create the correct cut outs.

So I just wanted to warn RC-F owners.

Attached Thumbnails Carbotech 1521 problems. Unhappy buyer.-oem-front-more-side-view-copy.jpg   Carbotech 1521 problems. Unhappy buyer.-carbotech-fronts-with-wrong-sensor-slots-copy.jpg   Carbotech 1521 problems. Unhappy buyer.-5k-miles-uneven-patterns.jpg   Carbotech 1521 problems. Unhappy buyer.-zoom-uneven-area.jpg  
Old 08-09-16, 02:14 PM
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Deanrcf
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Thanks for the write up. I guess I'll be waiting longer to see what Hawks and others will do.
Old 08-09-16, 03:00 PM
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Davew77
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Yeah... I'll be staying away from those.

I'm happy with the OEM pads anyhow. As for the brake dust, that's my detailer's problem.
Old 08-09-16, 03:27 PM
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Deanrcf
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Originally Posted by Davew77
Yeah... I'll be staying away from those.

I'm happy with the OEM pads anyhow. As for the brake dust, that's my detailer's problem.
Are you referring to original brake pads or post TSB pads?
Old 08-09-16, 03:29 PM
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SpeedFreaksUSA
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I'm sorry to see these didn't work out so well for you. We have had an incredible amount of success with the Project Mu Type NS / NS400 on the IS-F and are working with them to come up with a better solution for an ultra low dust street performance pad on the RCF. Project Mu is a top tier brand and they should be able to perfectly replicate the intricacies of the RCF backplates (specifically the wear sensor slots). Will let you know more as we get closer to wrapping up the first production run in the next couple months.

-Matt M.
Old 08-09-16, 03:39 PM
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Carnevino
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you could get you wheels done in Cquartz and then just hose the dust off easily. I'm getting mine done next Monday. Just a thought
Old 08-09-16, 03:46 PM
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Davew77
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Originally Posted by Deanrcf
Are you referring to original brake pads or post TSB pads?
Mine are the pads that were on the car when it came from the factory. I wasn't even aware there was a TSB. I haven't had any issues other than dust.

What was the TSB for?
Old 08-09-16, 03:53 PM
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Danblanco
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This is what scares me about using aftermarket pads. The OEM pads will throw you through the windshield, I'm with Davew77 I don't care about the dust, but I hate the squealing that the OEM pads do under gentle braking. My SRT Jeep had Brembo brakes and did the same thing squeak and lots of dust I put aftermarket pads on and the dust and squealing went away and so did the great stopping power.
Old 08-09-16, 04:48 PM
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Deanrcf
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Originally Posted by Davew77
Mine are the pads that were on the car when it came from the factory. I wasn't even aware there was a TSB. I haven't had any issues other than dust.

What was the TSB for?
i saw something posted about a bulletin for brake dust. There are supposedly installed by dealership and creates less dust. This is my second car with factory Brembo brakes. The first had dust too, but were only 4 pot and 2 pot. More pots, more dust. The RCF fronts get way more dusty than the rears.
Old 08-09-16, 04:51 PM
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https://www.clublexus.com/forums/rc-...-oem-pads.html
Old 08-09-16, 05:03 PM
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Davew77
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Interesting... I've only had them squeal one time that I know of. But even then it didn't bother me. I'm not even sure what the conditions were that may have caused them to squeal. But I'm guessing that the rotors were pretty hot since I was having a lot of fun in the car and I did light braking when I was pulling into my garage. Now if they always squealed it would likely start to get on my nerves. But so far it was only the once that I know of (I sometimes have the stereo pretty loud).

As for the dust, I don't know how bad it is or isn't since I'm not the one who cleans the rims. When I'm not at an automatic washer my detailer is cleaning my car. However, I do know that my detailer has mentioned the brake dust and how much fun he had removing it..

I'm guessing not all of the factory pads have the same issues, at least with squealing.



Edit: I just thought about bedding. I wonder if everyone with squealing issues properly bedded their brakes?

I also don't do light braking very often. I was always taught that braking lightly for a longer time was worse on your pads and rotors than firm braking for a shorter time.

That's all I got.

Last edited by Davew77; 08-09-16 at 06:07 PM.
Old 08-09-16, 07:14 PM
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flowrider
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Originally Posted by Davew77
Edit: I just thought about bedding. I wonder if everyone with squealing issues properly bedded their brakes?

I also don't do light braking very often. I was always taught that braking lightly for a longer time was worse on your pads and rotors than firm braking for a shorter time.

That's all I got.
I certainly agree, proper brake bedding is extremely important. It transfers the pad material to the rotor improving performance and lessening noise. I have Ferodo DS2500 pads in front, and Project Mu HC+800 pads in back. Both bought from Forum Sponsor SpeedFreaks (posted above) IMHO, a wonderful dual purpose combo.

I disagree with you comment on light braking vs heavy braking. I try to anticipate when I need to stop (Traffic lights, slower cars, and etc) and gently pump my brakes (if I have sufficient distance) before needing to stop. IMO this dissipates heat better and lengthens rotor and pad life. I have done this all my life (which as been a very long time)

I picked this up from a brake "expert"

For pure stopping power, you want to brake as hard and as fully as possible without either locking the brakes or going into an uncontrolled skid. The stopping power is always dependent on the traction the tires have on the road, not just the friction of the brake pads on rotors. Most modern passenger cars have some kind of anti-lock brakes, meaning, for maximum emergency stopping power, you should generally stomp on the brake pedal as hard as possible and let the automated controls "pulse" the brakes to control the deceleration. If you do not have anti-lock brakes, then you may need to manually "pump" the brakes for hard stopping or wet-road conditions, to avoid locking up the brakes/wheels and going into an uncontrolled skid. That becomes a more complicated question.
  • For overall fuel-economy and vehicle-life in everyday driving, the best approach is usually to drive in a fashion that minimizes brake-usage as much as possible: e.g., leave plenty of room ahead of you, coast to stops as much as possible, decelerate by taking foot off the gas early rather than by putting foot on the brake, etc.
  • Following the above, it doesn't much matter in a strict engineering sense whether you achieve the same amount of deceleration with long, continuous pressure or intermittent pulsing, both involve the same amount of friction to achieve the same stopping power.
  • "Pumping" the brakes to control heat-dissipation would require more skill than I think any human driver has (the strategy would be to hit only "cold" patches of the rotor on every rotation). This qualifies as over-engineering, unless your car lacks anti-lock brakes or there is something special about the driving conditions.
  • Driving in difficult/unpredictable conditions such as snow/mud/puddles etc can sometimes test the limits of anti-lock brakes. In such conditions, it can be useful to frequently pump the brakes to dry them and test them.
  • The above should be used with caution: on icy or wet roads, where partial skid/hydroplaning can occur, it is best to shift into low gear and to drive into the skid with foot off the pedals, to allow the wheels to regain traction in a direction where they are not fighting the momentum of the car.
PS-- brakes will always over-power the engine, and most modern automatic transmissions are smart enough to accommodate braking. In fact, automatics are usually better than even extremely-skilled drivers when it comes to most emergency handling. Skilled stick-shift sports driving is about things like controlling skids and maximizing acceleration. Automatics are better at ending the skid and regaining traction.
Lou
Old 08-09-16, 07:44 PM
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Davew77
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Originally Posted by flowrider
I disagree with you comment on light braking vs heavy braking. I try to anticipate when I need to stop (Traffic lights, slower cars, and etc) and gently pump my brakes (if I have sufficient distance) before needing to stop. IMO this dissipates heat better and lengthens rotor and pad life. I have done this all my life (which as been a very long time)
What you do sounds like a good idea.

I have always used engine braking myself. I do it in my RC F as well. I'm usually in manual mode anyway, so I downshift and let the engine slow the car. Then I apply the brakes firmly if engine braking alone is not going to be enough to slow me as much as needed. When I say firmly, I don't mean putting my face on the windshield.

That quote you posted about it requiring the same amount of friction to stop no matter how hard you brake also makes sense. I never gave it much thought, I just did as I was taught. But now that I think about the physics of it, it should take the same amount of force to stop no matter what amount of force is applied at once. As such, it should create the same amount of friction and heat. Your way would allow the heat to dissipate a little since it could cool between brake applications. But it requires more time and distance.

Light braking would create the same amount of friction according to that quote. The heat generated would probably be less intense since it is generated over a longer period of time. But having it persist for a longer period of time could possibly cause the pads to glaze over. Which could lead to squealing. I'm no expert on brakes. I'm only offering a theory. Using engine braking reduces the heat put on my pads, which may also be part of the reason I do not have squealing problems.
Old 08-10-16, 06:01 AM
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I had the same problem with the wear sensor when installing the carbotech rear pads as well. I took a small cutoff wheel on the Dremel and cut a groove on either side of the slot in order to get the plastic sensor to slide in, then I ran a cut perpendicular to those to make sure the retainer clip had something to clip on to. For $500 they should've been perfect! They claim they reuse the front factory backing plate, why not the rears??? The rears also slide back and forth a little creating a clicking noise sometimes when going from drive to reverse or vice versa, but that could be b/c I didn't put any grease between the pad and the stainless steel factory plate that clips onto it. Other than that they're fine so far, but I'm not at 20K yet only have a couple thousand miles on them.
Old 08-10-16, 06:04 AM
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Someone had posted earlier that there is a warning from Lexus HQ if you switch to the less dusty/noisy pads, your braking/stopping distance will be increased. Personally I want to have the ability to stop sooner and in shorter distance versus some brake dust or noise.

Incidentally when I first got my other car, MB SLK55AMG It came with high performance Brembo brakes and it was very noisy and dusty. I bedded the brakes and the noise is much better. However, the dusty problem persists.


Originally Posted by Deanrcf
i saw something posted about a bulletin for brake dust. There are supposedly installed by dealership and creates less dust. This is my second car with factory Brembo brakes. The first had dust too, but were only 4 pot and 2 pot. More pots, more dust. The RCF fronts get way more dusty than the rears.


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