Can I get your opinions on my front rotors

[Jim2000]

I had an ATS-V and after using OEM parts, I still had vibration issues after about 8k miles on the new rotors and pads. I turned the rotors and the vibration returned 2k miles later. Cadillac has a huge problem with the brakes on these cars. The price is ridiculous for a brake job on the fronts. Do we really need to stop that fast? Only if you are on the track which most of us will never do.

 

[Seth]

I think you should get a second opinion.

Have an appointment Thursday morning with a shop I trust. Will report back!

 

[jodakid69]

This is a long and detailed post as requested ... a brain dump. Forum members, please keep me honest and call out any errors. My disclaimer is that the solution I discuss in this posting is a non-Cadillac solution. I am neither a mechanic nor an automotive engineer.

I have "self-diagnosed" that the core problem that we, the Cadillac CT4V-BW / CT5V-BW community as a group is running into with the so-called "rotor warping" is actually rotors that have exceeded the maximum assembled lateral runout (LRO). In layman's terms, the rotor develops an uneven thickness.

If you experience this issue and you get the dealer to replace the rotors under warranty then, please use that route to resolve the issue! New hardware is always a preferred solution. However, if you are paying for new rotors and the rotor discs are still within specification for thickness, then read on .....

THE PROBLEM:
(a) Uneven brake pad burnishing for the stock OEM brake pads and rotors MAY be a primary cause of low mileage rotors that attain a state where they exceed the maximum assembled lateral runout (LRO).

(b) repeated anti-lock brake engagement, either during street or track use MAY be a primary cause of low mileage rotors that attain a state where they exceed the maximum assembled lateral runout (LRO).

THE SYMPTOM:
Brake system vibration that is experienced at the steering wheel or brake pedal.

THE SOLUTION:
If the rotors exceed the maximum assembled lateral runout (LRO) they MAY need to be replaced. This is the dealer solution. This is also the best solution if new rotors are covered under warranty.

The home brew solution. Install Sintered Brake Pads - these pads will remove NOA brake pad deposits after 1 or 2 track days with multiple hard but not ABS braking at a speed of 120+MPH.

THE "NON-ENGINEER" RATIONALE FOR WHY THE SOLUTION WORKS:
If the cause of rotors that have exceeded the maximum assembled lateral runout (LRO) is uneven brake pad deposits, then the use of Sintered metallic brake pads MAY remove those deposits and reduce or eliminate the problem.

Sintered metallic brake pads work by using direct metal-to-metal friction rather than deposit-on-deposit friction. They will remove the deposits made OEM brake pad under heavy braking.

Note that I am not the only person suggesting this state and or solution:
This screen capture is from the forum Thread - ct4 v blackwing upgraded rotors.

MY PERSONAL EXPERIENCE WITH BRAKE VIBRATION:
I experience brake vibration after 3 track days - approx mileage 5K. Three dealers stated that I had "warped rotors" due to track use and that the rotor replacement was not covered under warranty and would be in the $2500 range.
After two track days using EBC SR11 brake pads, the significant brake vibration during medium to hard braking that I was experiencing has been corrected.

Therefore, my issue has likely caused by heavy ABS braking using the stock pads.

Note that EBC SR11 will make your initial brake bite harder and stop quicker. You may not like this effect. I love it. Just brake softer when you don't need it. But many people may not like the effect. If that is you, then use the pads to fix the problem and then replace them with OEM pads. It beats a $2500 rotor replacement.

INFORMATION ON THE BLACKWING BRAKE SYSTEM:
(1) - The "steel rotor" Blackwings CT4V/CT5V (option J6G) brakes use Non-Asbestos Organic (NAO) Brake pads.
This brake system has a Hat and a Disc that as a unit makes up the complete Rotor.

Currently, GM is selling the rotor as a complete unit - Hat and Disc.

(2) NAO style brake pad function, "generate friction", using NAO deposits on rotors to the NAO brake pads.
This is the reason that the owner's manual stated that you need to burnish your brake pads prior to track use, when heavy friction is required to generate heavy braking.

(3) Brake Burnishing - Direct from the CT4V-BW Owners Manual:
For vehicles equipped with front Brembo brake systems: Performance/racing brake pads are required prior to racing or closed-track driving. Vehicles with option code JE2 have performance brake pads. New brake pads must be burnished before racing or other competitive driving.

More details are provided in the Service Manual - Document ID 2082996
(a) accelerate to 30PMH, hard brake with no anti-lock, allow cooling of brakes and repeat 20 times

The new vehicle break-in period should be completed before performing the brake burnish procedure, otherwise damage may occur to the powertrain/engine.

(4) NAO brake pad use can under specific conditions lead to assembled brake rotor lateral runout that exceeds the specification and causes thickness variations to develop on the rotors. Reference Service Manual document 2082849. It is this rotor state, a rotor that has out-of-spec LRO, that many people are referring to as "warped rotors". This is not heat metal deformation, what many people envision as warped metal rotors.

(5) NAO brake pads are a great "compromise brake pad" for street and light track use, reference the chart below:

(6) - Brake Dust, per brembo, is rotor dust not brake pad dust. Therefore by inference, if a brake pad is generating dust, it is eating up your rotors.

(7) - The Blackwing NAO brake pads function by depositing a thin layer of brake pad deposits on the rotor.

(8) - When exposed to heavy braking, and especially ABS braking, the deposits on the rotor become uneven. Likely this is caused by the ABS action

(9) - If exposed to heavy braking, like at the track, rotors get very hot. If you then hold the brake you might transfer brake pad material on the rotor unevenly.

(10) - The Blackwings use an extra caliper and brake pad on the rear brakes. However, if you set the parking brake when the rotors are hot after heavy braking you might also add more deposits. But these would be on the rear rotors, and the problems seem to be more front rotor related. I do not know if cold rear parking brake pads are more or less likely to add deposits than hot rear brake pads. But this would affect only the rear brakes, not the front brakes.

===============================================================

Sintered brake pad overview from my friend ChatGPT:

Sintered brake pads are a type of brake pad commonly used in high-performance and heavy-duty applications, such as racing vehicles and motorcycles. They are made from a combination of metallic particles and other materials that are compacted and fused together using heat and pressure. Here's how sintered brake pads work:

• Friction Material: The main component of sintered brake pads is a mixture of metal particles, such as copper, bronze, iron, or steel, combined with other additives. This mixture is designed to create a strong and stable friction material that can withstand high temperatures and heavy use.
• Manufacturing Process: The raw materials are mixed, compacted, and then subjected to a high-temperature sintering process. During sintering, the metal particles are fused together, creating a solid and porous structure with uniform friction properties.
• Braking Action: When you apply the brakes, the brake caliper squeezes the brake pads against the brake disc (rotor) on each wheel. This action generates friction between the sintered brake pads and the brake disc, converting the kinetic energy of the moving vehicle into heat energy.
• Heat Dissipation: Sintered brake pads are specifically designed to handle high levels of heat. The porous structure of the material allows it to disperse heat effectively, preventing the brakes from overheating during intense braking situations, such as repeated heavy braking or driving downhill.
• Consistent Performance: Sintered brake pads provide consistent and predictable braking performance over a wide range of temperatures. This characteristic makes them ideal for high-performance vehicles, off-road use, and situations where braking conditions may be more demanding.
• Durability: Sintered brake pads generally have a longer lifespan compared to other types of brake pads, like organic or semi-metallic pads. Their robust construction and ability to withstand heat contribute to their durability and resistance to wear.
• Brake Dust: One downside of sintered brake pads is that they tend to produce more brake dust compared to organic pads. This is due to the metal particles and abrasive nature of the friction material.

Overall, sintered brake pads are an excellent choice for high-performance and heavy-duty applications where consistent and reliable braking performance is crucial. However, for everyday driving or less demanding conditions, organic or ceramic brake pads may be preferred due to their quieter operation and lower dust generation. Always consider the specific needs and requirements of your vehicle and driving style when choosing the appropriate brake pads.

 

[jodakid69]

I had an ATS-V and after using OEM parts, I still had vibration issues after about 8k miles on the new rotors and pads. I turned the rotors and the vibration returned 2k miles later. Cadillac has a huge problem with the brakes on these cars. The price is ridiculous for a brake job on the fronts. Do we really need to stop that fast? Only if you are on the track which most of us will never do.

Read about my solution, the EBC EC11 pads are actually for the ATS-V. The rear pads are actually a tad small as the rear caliper for the CT4V-BW is different.

 

[sleepys4]

I had my rotor resurfaced. Honestly hard to find a shop the rotors will fit on, but they have been fine since switching from stock pads. I run HPS 5.0 on the street and DTC70/60s for the track.

Would love for everybody to email Girodisc so they can see the demand. DBA would be good to email as well.

Jordan

 

[FI Fiend]

This is a long and detailed post as requested ... a brain dump.

Thanks for the information. Any negative experiences with the pad swaps?

Possible considerations for me would be weather the higher heat generating sintered material would be a challenge for the braking system (fluid etc) especially since there isn't direct temperature monitoring. There is a lot of thermal considerations in the design so maybe it doesn't matter.

Next would be whether the sintered pad in some way effects the surface of the rotor such that switching back to the NAO pad is problematic. Thinking overall surface finish/roughness, material transfer. There redoing a burnishing process would circumvent.

 

[jodakid69]

One thing that I forgot to include in my GM quality survey is that I absoutely hate the brake feel. For such a 'large' performance brake, the mid braking feel is shit. It feels like the car is sliding for sudden stops unless you stomp on the brake which I have never done since it's still a new car.

One thing that I forgot to include in my GM quality survey is that I absoutely hate the brake feel. For such a 'large' performance brake, the mid braking feel is shit. It feels like the car is sliding for sudden stops unless you stomp on the brake which I have never done since it's still a new car.

The CT4V-BW has a brake-by-wire system. Your stopping feedback on the pedal is not coming from the system directly.

(1) You might try this:
Brake Burnishing - Direct from the CT4V-BW Owners Manual:
For vehicles equipped with front Brembo brake systems: Performance/racing brake pads are required prior to racing or closed-track driving. Vehicles with option code JE2 have performance brake pads. New brake pads must be burnished before racing or other competitive driving.

(2) Or if you switch out to EBC EC11 pads, your braking power will increase. My experience is that these pads have much more of an "initial bite" when pressing the brake pedal than the stock pads have. However, what you gain in stopping power, you will lose on brake dust, brake squeal, shorter life on the rotors, etc.

I actually think that the Cadillac Brembo team did a great job on the braking system. However, we seem to have this issue with brake pad deposit. An awareness would go a long way to avoiding or fixing this potential issue.

Alternate brake pad selection all depends on how you are driving, street versus track, the terrain, and what you want out of your driving experience. If you are doing a lot of driving in stop-and-go traffic, do not use the EBC EC11 pads. They will not give you a smooth "Caddilac" style stopping experience. But, if you do country road driving in curves or go on the track, you will probably really like these brake pads.

 

[jodakid69]

Thanks for the information. Any negative experiences with the pad swaps?

Possible considerations for me would be weather the higher heat generating sintered material would be a challenge for the braking system (fluid etc) especially since there isn't direct temperature monitoring. There is a lot of thermal considerations in the design so maybe it doesn't matter.

Next would be whether the sintered pad in some way effects the surface of the rotor such that switching back to the NAO pad is problematic. Thinking overall surface finish/roughness, material transfer. There redoing a burnishing process would circumvent.

Hello FI Friend, I see that you are in South Jersey. Please come out this Saturday, July 29th for the Cars and Coffee event at NJMP. A Cadillac dealer will be at the event, and we are hoping to have numerous V-Performance owners to talk with and discuss all aspects of V-Performance vehicle ownership. For more details, search for my announcement posting.

As far as the downsides to switching pads, the answer is yes there are. Sintered brake pads will generate more dust, more brake squeal, and shorter rotor life (wear). However, my perspective is that in my use case, the rotor life was 5K miles. I am not the only person that is having this short rotor life, as diagnosed by Cadillac dealers are calling for non-warranty rotor replacements. Therefore, the EBC Sintered brake pads are actually allowing me to keep the original rotors without making a non-warranty rotor replacement. But the total life of the rotors will be decreased from wear.

The higher heat levels should only come into play on the track, not in street use. If you are in fact going to track your car on a repeated basis, I suggest switching to a racing brake fluid, regardless of the brake pads. Again, the downside of using a racing brake fluid is the higher cost of the initial and subsequent brake fluid changes. You will need to do yearly brake fluid changes when using Racing brake fluids such as Castrol SRF. FYI, you need 2 liters per fluid change not just 1.

 

[Seth]

I noticed the C&D test car has over 30k miles on it with no mention of brake work needed, but they're also somehow averaging 21MPG so... not sure they are doing much other than highway driving.

 

[jodakid69]

I noticed the C&D test car has over 30k miles on it with no mention of brake work needed, but they're also somehow averaging 21MPG so... not sure they are doing much other than highway driving.

I had 3 track days where I was doing hard stops from 125MPH+ when the brake vibration issue started. The ABS system was engaging. I am not sure that the C&D test car has been doing this type of driving, certainly not with that gas mileage.

 

[PL69]

I had 3 track days where I was doing hard stops from 125MPH+ when the brake vibration issue started. The ABS system was engaging. I am not sure that the C&D test car has been doing this type of driving, certainly not with that gas mileage.

View attachment 20599

I had vibrations after a track day that the abs engaged often, I'm at another fast track where I don't need as much braking and the more the day is going the less vibrations I have.

These OEM pads seem to be very sensitive to abs hot spotting, I had the same problem in my M3 but even worse because of the drilled rotors

 

[Carguyshu]

That is hilariously overpriced

 

[Seth]

This second shop is also recommending replacement and is quoting the same price. Pads are at 4mm, and "hotspots are worn into the brake disc. Heat spots will cause noise with new pads."

They are quoting labor as $472.50 and parts as $2697 (rotors 999 each and pad set 699), to replace front rotors and pads.

Maybe I am getting into stupid question territory but is it correct that I will need:

Rotor - Right

Rotor - Left

Front Brake Pad Set

Even if I pay $100 in shipping that brings my parts cost down to $1775, reducing my total by over $900

Thoughts?

 

[RDATLTE]

This second shop is also recommending replacement and is quoting the same price. Pads are at 4mm, and "hotspots are worn into the brake disc. Heat spots will cause noise with new pads."

They are quoting labor as $472.50 and parts as $2697 (rotors 999 each and pad set 699), to replace front rotors and pads.

Maybe I am getting into stupid question territory but is it correct that I will need:

Rotor - Right

Rotor - Left

Front Brake Pad Set

Even if I pay $100 in shipping that brings my parts cost down to $1775, reducing my total by over $900

Thoughts?

The labor seems high for the job as well. That's got to be for 3-4 hours of labor that they're quoting for that job.

 

[DCV]

Rotors and pads are easy to change.

 

[Jim2000]

This second shop is also recommending replacement and is quoting the same price. Pads are at 4mm, and "hotspots are worn into the brake disc. Heat spots will cause noise with new pads."

They are quoting labor as $472.50 and parts as $2697 (rotors 999 each and pad set 699), to replace front rotors and pads.

Maybe I am getting into stupid question territory but is it correct that I will need:

Rotor - Right

Rotor - Left

Front Brake Pad Set

Even if I pay $100 in shipping that brings my parts cost down to $1775, reducing my total by over $900

Thoughts?

These rotors can be turned. Why spend $2k when you can turn them for $300?

 

[Neveready]

This second shop is also recommending replacement and is quoting the same price. Pads are at 4mm, and "hotspots are worn into the brake disc. Heat spots will cause noise with new pads."

They are quoting labor as $472.50 and parts as $2697 (rotors 999 each and pad set 699), to replace front rotors and pads.

Maybe I am getting into stupid question territory but is it correct that I will need:

Rotor - Right

Rotor - Left

Front Brake Pad Set

Even if I pay $100 in shipping that brings my parts cost down to $1775, reducing my total by over $900

Thoughts?

$500 cheaper than the dealer. If you can tackle it yourself and you can actually get the parts from that website for that price then that's something you can knock out in a day. But if you don't have the tools, time or the knees to do it then just pay them. Labor at $472 seems high but if you trust them they probably want to cover themselves for spare time if they run into any problems.

I don't have a lift but if I did a brake job in my garage on a car I've never worked on it would be about a 3hr job, a shop could probably knock that out in a little over 2 hrs assuming there's no issues. If you wanted the service manual for DYI you can get that for $22.

 

[Seth]

The lowest price the mechanic could quote was $2850 (post-tax) for replacing the front pads and rotors. Still feels too high given that I can get the parts myself for $1800. I'm going to just kick the ball down the court here, and figure something out. He said I have a few thousand miles left of usable life, and I'm not having any brake issues or vibration as things stand.

 

[poor-sha]

Are the pads to the wear sensors yet? Did they say 4mm of pad material or total pad thickness? I just measured my pads as I thought they were kind of low and the backing plate is 6mm thick and I had another ~6mm of pad material and it hadn't started wearing the wear sensors yet. Caveat being these are CCB brakes, but I doubt the thickness will differ.

If I were you, I'd pull the wheels and slam some new pads in, then see if you can get the rotor judder to go away. I just pulled all four sets of pads off of my car to check them. Rotors are a bit more tricky because the torque setting on the front caliper bolts is 111 lb ft + 15-30 degrees. That can be kind of tough to do unless you are under the car on a lift.

When I've had issues with brake judder in the past (different car, F80 M3), the way to get rid of it was to get an aggressive track pad and drive them around on the street where they are cold. Track pads are very abrasive until they heat up, and gentle braking will wear off the pad deposits on the rotors. It takes a few days but it works. I don't know if the stock pads are abrasive enough when cold to do it.

Once you get this sorted out, I'd properly bed the brakes without getting into the ABS so you have a smooth transfer layer.

 

[Seth]

Are the pads to the wear sensors yet? Did they say 4mm of pad material or total pad thickness? I just measured my pads as I thought they were kind of low and the backing plate is 6mm thick and I had another ~6mm of pad material and it hadn't started wearing the wear sensors yet. Caveat being these are CCB brakes, but I doubt the thickness will differ.

If I were you, I'd pull the wheels and slam some new pads in, then see if you can get the rotor judder to go away. I just pulled all four sets of pads off of my car to check them. Rotors are a bit more tricky because the torque setting on the front caliper bolts is 111 lb ft + 15-30 degrees. That can be kind of tough to do unless you are under the car on a lift.

When I've had issues with brake judder in the past (different car, F80 M3), the way to get rid of it was to get an aggressive track pad and drive them around on the street where they are cold. Track pads are very abrasive until they heat up, and gentle braking will wear off the pad deposits on the rotors. It takes a few days but it works. I don't know if the stock pads are abrasive enough when cold to do it.

Once you get this sorted out, I'd properly bed the brakes without getting into the ABS so you have a smooth transfer layer.

Yeah, I probably won’t be doing this full job at home. I like to DIY things when I can but not sure I want to mess around with brakes.

What’s the recommended bedding procedure for these brakes?