2020 Mustang GT Rear Rotors are Marked and Look Like a Record

[njweatherman]

Hello everyone! I'm new to the Mustang world. I came from a 2ss Camaro.
Back in December 2020, I bought a brand new 2020 Mustang GT Premium California Special, Non PP, with active exhaust. Back in early March, I noticed the rear rotors were scratched; more so on the passenger side. See attached images.

I took it to the nearest Ford dealership and the tech said, "No repair necessary, Normal rust ring build up." So, a few weeks later, I took it to the Ford dealership I bought it from and the service manager had a tech drive the car. The service manager confirmed the markings on the rotors, but since the tech did not find a drive-ability issue, they could not do anything. Any suggestions on how I should proceed? Currently, I have 2700 miles on the car. THanks!

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[Soulja4187]

I had the same issue with my 2020 GT Premium PP1 that I bought in April of 2020. I never had a car that the rotors had such deep grooves caused by the pads. I first noticed it when the car had 6000 miles. When I took the car to the dealer for other issues I showed them the rotors and they told me that it was normal. The Accord I had prior to this car had the same rotors for 75000 miles and Honda is known for making softest rotors but they never had score like my 2020. I now have a 2021 GT Premium PP1 and so far they look good.

 

[njweatherman]

Thank you for the reply. Did you ever feel any brake pedal pulsation?

 

[Soulja4187]

Thank you for the reply. Did you ever feel any brake pedal pulsation?

Yes I did feel pulsation and slight steering vibration when slowing down quickly.

 

[njweatherman]

I definitely don't feel any steering wheel vibration. However, it is hard to tell if I feel a slight pulsation in the brake pedal. I contribute that to the active exhaust vibration and the Pirelli Zero Nero all season tires.

 

[shogun32]

hard to tell if I feel a slight pulsation in the brake pedal. I contribute that to the active exhaust vibration and the Pirelli Zero Nero all season tires.

eh? AE doesn't vibrate and as sucky as the PZ Nero are they don't slip/skid/grip unless the surface is lousy and they are cold. There should be nothing but firm, consistent feel at the pedal.

Run your fingernail across the rotor in radial fashion - does it catch multiple ridges or have easily felt waves (valleys) in the rotor face? If not, no need to worry. If yes, you need to have a shop pull the pads and see what's gouging the rotor. If the rotor is damaged (not smooth and flat) then Ford should be replacing both rotors and pads.

 

[njweatherman]

When I run my finger along the rotor, I can definitely feel the lines/grooves. I read on a forum to use a dime and see if it gets caught in the grooves. I tried it and the dime did not get caught in any of the grooves.

 

[Freedom]

my rears are like that. 26K miles so far no vibration issues.

 

[Norm Peterson]

When I run my finger along the rotor, I can definitely feel the lines/grooves. I read on a forum to use a dime and see if it gets caught in the grooves. I tried it and the dime did not get caught in any of the grooves.

It looks like small bits of grit managed to get caught between the pads and the rotors - done any driving on dusty or dirt roads lately? If this is the case, it's not really the fault of any part, and slotted (not drilled) rotors may well solve it.


Fingernails are probably more sensitive than holding a dime.


Norm

 

[Soulja4187]

It looks like small bits of grit managed to get caught between the pads and the rotors - done any driving on dusty or dirt roads lately? If this is the case, it's not really the fault of any part, and slotted (not drilled) rotors may well solve it.


Fingernails are probably more sensitive than holding a dime.


Norm

Dusty or dirt roads should not cause that. I used to live in Georgia and the area I was living at was going through roads and home development. I had a 1 mile dirty road I used to get to my destination a bit faster and let me tell you that the rotors on the Honda Accord I had never had this kind of grooves and if you didn't know Honda uses the softness rotors out there.

Explain to me how my 2020 PP1 had the same grooves as the OP and all miles driven were on south florida highways.

 

[Norm Peterson]

On a brief search . . .

What is Florida's soil composition?
Tropical Florida soils tend to be composed of sand and limestone aggregates. A summary of the growing conditions in Florida: The soil is composed mostly of sand

Norm

 

[Soulja4187]

On a brief search . . .




Norm

Well my mom's Toyota Corolla, wife's IS300 , sister in law's Mercedes SUV and my brother's F250 truck none suffer from this and prior to the Mustang I had the Accord. I bought it new and the original rotors were on until the car had around 75000 miles. I think Ford was used a cheap supplier for rotors for the 2020's. On my 2021 PP1 so far I have 1200 miles and the rotors are still smooth.

 

[Norm Peterson]

The direction of rotor venting is probably involved somehow. I'm sure that there are other effects.


Norm

 

[sfs550]

Hello everyone! I'm new to the Mustang world. I came from a 2ss Camaro.
Back in December 2020, I bought a brand new 2020 Mustang GT Premium California Special, Non PP, with active exhaust. Back in early March, I noticed the rear rotors were scratched; more so on the passenger side. See attached images.

I took it to the nearest Ford dealership and the tech said, "No repair necessary, Normal rust ring build up." So, a few weeks later, I took it to the Ford dealership I bought it from and the service manager had a tech drive the car. The service manager confirmed the markings on the rotors, but since the tech did not find a drive-ability issue, they could not do anything. Any suggestions on how I should proceed? Currently, I have 2700 miles on the car. THanks!

Do the rear brakes squeek?

 

[njweatherman]

Thanks for all the replies guys! No, the roads here in NJ are paved. Only a few fire roads in remote northwest areas, but I never venture there. Thankfully, the brakes do not squeak and are quiet.
I agree with David (Soulja4187). I, like him, never have seen anything like this on my previous cars (2018 2SS Camaro, 2013 2ss Camaro, 2007 Silverado, 2001 Mustang GT). I'm curious if Ford put out a TSB to the dealerships and said not to change the rotors unless there is a vibration/pulsation or some other problem? FYI - I did a Google search and some of the F-150 trucks have the same issue.

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