Rotor grinding

[Striike]

Hi everyone. Just bought a 21 Mach E. Replaced the ugly wheels, and now I see some alarming wear on both rear rotors. Only 13k miles on it. Anyone else had this issue?
I can certainly have the rotors turned, but concerned I’ll have a problem in another 13k miles. What do you all think?
Please note the front rotors are spotless.

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[RickMachE]

Because the Mach-E uses blended braking, the rotors tend to rust due to lack of use. Drive at speed, making sure no one is behind you. Shift to N, then apply brakes to slow. Shift to D, get back to speed, shift to N, apply brakes. See if after a few of these if the rotors aren't clean.

 

[Mach-Lee]

Try the neutral braking procedure Rick suggested first. Do it like 5-10 times. Then see how the rotors look and go from there.

My car had really noisy brakes when it was new until I did the above. Adaptive cruise has to jam on the brakes enough in traffic so mine stay pretty clean, but if you live in a rural area and don't have to brake very hard, your rotors will get some rust and grooving like that.

EDIT: Also make sure you use your parking brake periodically, that may be how the rear adjuster works.

 

[Neil4Real]

EDIT: Also make sure you use your parking brake periodically, that may be how the rear adjuster works.

What does this mean?

 

[RickMachE]

What does this mean?

Self-adjusting by use.

 

[Mach-Lee]

What does this mean?

A brake adjuster moves the pads out slightly further with time to compensate for brake pad wear. Otherwise you would have to press the brake pedal further and further as the pads wore out to get braking.

On some cars the rear adjuster is only actuated by the parking brake. So if the owner never uses the parking brake, the rear brakes will be mostly useless because they will be out of adjustment. The rears look hydraulically adjustable on the Mach-E (not 100% sure), but still a good idea to use the parking brake every 500 miles so it doesn't seize up.

 

[hawkeye3point1]

I wish mine looked that good. Even though I regularly apply pad friction, the rear rotors are badly scored. Does anyone know what the criteria is in the WSM for machining the rotors?

 

[azerik]

:that^^: button.
Mine were all turned and new pads in the front from the SSM. But they look just like yours after 200 ish miles. Run it to the dealer and get it done under warranty first. And the SSM for the crappy front pads with the split line through them.

For the SSM they visually look for pad material. They told me I had material on all 4 rotors. (I bedded the crap out of them about 400 miles before taking it in, didn’t make it worse, but didn’t make it better)I had the shudder when trying to use the brake pedal.

 

[Mach-Lee]

I wish mine looked that good. Even though I regularly apply pad friction, the rear rotors are badly scored. Does anyone know what the criteria is in the WSM for machining the rotors?

Doesn't say much:

NOTE: Do not machine the brake discs for any brake noise concern (squeal, squeak, moan, groan, grunt, grind, etc.). Brake disc machining is allowed if one of the below conditions is present;

• • Excessive corrosion/rust and/or pitting on the braking surface.
  • Excessive bluing discoloration and/or heat spots on the braking surface.
  • Scoring of the brake disc surface.

Keep in mind the brake warranty is only 12 months / 12k I believe.

 

[dbsb3233]

EDIT: Also make sure you use your parking brake periodically, that may be how the rear adjuster works.

I almost never apply the parking brake manually, but it does come on automatically when parking on even a modest slope. Like for instance when I park in my driveway (normal driveway slope).

Disengages automatically too when putting it in D and pressing the accelerator pedal, but that creates a too-fast lurch (2P driving). So I've learned to manually release it with the button.

Anyway, good chance it's engaging already without people necessarily realizing.

 

[Logal727]

:that^^: button.
Mine were all turned and new pads in the front from the SSM. But they look just like yours after 200 ish miles. Run it to the dealer and get it done under warranty first. And the SSM for the crappy front pads with the split line through them.

For the SSM they visually look for pad material. They told me I had material on all 4 rotors. (I bedded the crap out of them about 400 miles before taking it in, didn’t make it worse, but didn’t make it better)I had the shudder when trying to use the brake pedal.

I had the shudder on my trip recently, but it went away after hard braking. It really is just the build-up on the rotors from infrequent use. Take a long stop and go trip in Whisper mode, should take care of it.

 

[Mach-Lee]

I almost never apply the parking brake manually, but it does come on automatically when parking on even a modest slope. Like for instance when I park in my driveway (normal driveway slope).

Disengages automatically too when putting it in D and pressing the accelerator pedal, but that creates a too-fast lurch. So I've learned to manually release it with the button.

Anyway, good chance it's engaging already without people necessarily realizing.

Mine never engages because where I park is always flat. Colorado it gets used, North Dakota it might not. So it totally possible for someone to go 10k without using their parking brake if they always park in the same flat spots.

Also, if you learn to barely press the pedal like 1mm you can disengage the parking brake smoothly in one go. Harder to do on a hill though.

 

[Logal727]

Hi everyone. Just bought a 21 Mach E. Replaced the ugly wheels, and now I see some alarming wear on both rear rotors. Only 13k miles on it. Anyone else had this issue?
I can certainly have the rotors turned, but concerned I’ll have a problem in another 13k miles. What do you all think?
Please note the front rotors are spotless.

My Ford dealer was selling a 5yo Tesla and the rotors looked like a pizza stone because of the build up lol

 

[Blue highway]

Try the neutral braking procedure Rick suggested first. Do it like 5-10 times. Then see how the rotors look and go from there.

My car had really noisy brakes when it was new until I did the above. Adaptive cruise has to jam on the brakes enough in traffic so mine stay pretty clean, but if you live in a rural area and don't have to brake very hard, your rotors will get some rust and grooving like that.

EDIT: Also make sure you use your parking brake periodically, that may be how the rear adjuster works.

I've done brakes on other cars with disk rear brakes... on those, the parking brake is actually a separate drum type brake inside the rotor. The parking brake is separate from the rear disk brakes on those. (BMW and Cadillac)

Does anybody know if Ford does the same or do they actuate the rear disks when the parking brake is engaged?

 

[azerik]

I had the shudder on my trip recently, but it went away after hard braking. It really is just the build-up on the rotors from infrequent use. Take a long stop and go trip in Whisper mode, should take care of it.

Mine would shake the wheel out of your hand. Oh so fun to explain to my wife.

Does anybody know if Ford does the same or do they actuate the rear disks when the parking brake is engaged?

You can hear it run the worm gear in as it is turned on or off. So it applies manual pinching. That's why if that thing doesn't disengage you'll have a heck of a time moving. I stopped using the P brake if it's rainy out just to try to avoid that.

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