Brake Discs Wear Problem?

[ChristianPierre]

Hi!
I recently got my second MACH E, this time a LR and the previous one was a SR. My college got the SR and I ordered a LR instead.

On both vehicles I have noticed that the rear brake discs are looking bad. The SR have only run about 10 000 km and have already big tracks in them. You can both see and feel them. The dealer is now going to change them (on warranty I hope).

On the new LR I saw that the rear break discs looked bad already at the dealer. I took a photo of it and will tell the dealer to change them on the warranty aswell. Se attached photos.

Is this a common problem of the Mach E? I looked at the other new Mustang Mach E at the dealer and nearly all of them looked bad except for their demo.

The front break discs looked good on all veichles.

On our previous Ford Kuga PHEV 2020 we had to change rear brake discs at 50 000km.
Maybe this is just a common Ford problem?

Christian

 

[billyp]

Looks like rust because the brakes probably aren't being used much due to the regenerative braking.

 

[generaltso]

The friction brakes get a lot less use in an EV with regenerative braking, so rust can build up. You can brake hard every once in a while to force the friction brakes to be engaged and help strip the rust off.

 

[ChristianPierre]

I know the brakes doesnt get used much in an EV. Ive had a Model 3 for 60 000km before I changed to Mach E and never had any problems before.

The pictures are taken at the dealer before I bought it.

On the SR its not only rust, it has deep tracks around the discs. Just like if there had been stones or something sharp between the disc and the brakes..

Christian

 

[Pushrods&Capacitors]

I know the brakes doesnt get used much in an EV. Ive had a Model 3 for 60 000km before I changed to Mach E and never had any problems before.

The pictures are taken at the dealer before I bought it.

On the SR its not only rust, it has deep tracks around the discs. Just like if there had been stones or something sharp between the disc and the brakes..

Christian

If your rear rotor surfaces are grooved it is probably a pad issue. Rear brakes typically don’t see much wear because the fronts do the bulk of friction braking due to weight transfer -physics 101. However, beginning in the ‘90s, manufacturers began proportioning more braking force to the rear brakes as electronic systems allowed finer tuning of front to rear balance.

I suspect the MME and it’s heavy weight + near 50/50 weight distribution will show more rear rotor/pad wear than a typical cuv/suv. And I’d say that’s especially true for the RWD models.

 

[CHeil402]

I know the brakes doesnt get used much in an EV. Ive had a Model 3 for 60 000km before I changed to Mach E and never had any problems before.

The pictures are taken at the dealer before I bought it.

On the SR its not only rust, it has deep tracks around the discs. Just like if there had been stones or something sharp between the disc and the brakes..

Christian

The MME handles regenerative brake blending differently than Tesla. In a Tesla, you only get regen braking if you're using 1 pedal, once you press on the brake pedal it's 100% friction brake. Ford blends the two when using the brake pedal such that unless you're demanding more braking force than regen brakes can excerpt (e.g. slamming on the brakes), the friction brakes won't get used except to hold you at a stop.

Long story short, surface rust on EV brake discs is very common (and more common on MME than Tesla) and superficial. It will "feel" rough if you touch it but that doesn't mean that it's gouged. Try checking it again right after you park after a forceful brake or two.

 

[Sneezy]

Mine look worse than this after 4K miles. Time for an Italian brake tune up I guess.....

 

[SebastienMachE]

Just noticed my rear brake disk this morning. After 14000km.

This is not only rust, they are grooved!

 

[phidauex]

Just noticed my rear brake disk this morning. Adter 14000km.

This is not only rust, they are grooved!

Wow, it looks like maybe the pads are still breaking in, and in the meantime the rotor hasn't flattened. Could also be that some grit or something got into the pads, and their lack of use means it hasn't been scrubbed out as quickly as it would on another car.

Try this, put a sharpie line across the rotor, and then go do some fast stops (you need to stop pretty darn fast for the friction brakes to kick in). See how the mark is getting worn off.

My inclination is that it isn't really a problem, and is just a feature of the fact that these cars probably use their brakes 1/20th as often as an ICE, so it creates different looking wear patterns, but worth investigating a bit.

 

[louibluey]

I try to brake more aggressively and often during a drive to take the rust layer down once in a while (not the TSB problem, just rust from lack of use). I have not figured out the optimal amount yet, too much braking seems to make patterns in the rotors. The patterns are less than 360 around the rotor (very hard braking), not tracks all the way around. In my FE, it is much easier to shine up the fronts, so as noted above, the front brakes seem to do more braking work than the rear brakes.

 

[hybrid2bev]

Just noticed my rear brake disk this morning. After 14000km.

This is not only rust, they are grooved!

My passenger side rear rotors have 2 marks like that. My dealer said it was because a rock or something got stuck in there and then worked itself out. It's only the passenger side on mine.

 

[SebastienMachE]

Wow, it looks like maybe the pads are still breaking in, and in the meantime the rotor hasn't flattened. Could also be that some grit or something got into the pads, and their lack of use means it hasn't been scrubbed out as quickly as it would on another car.

Try this, put a sharpie line across the rotor, and then go do some fast stops (you need to stop pretty darn fast for the friction brakes to kick in). See how the mark is getting worn off.

My inclination is that it isn't really a problem, and is just a feature of the fact that these cars probably use their brakes 1/20th as often as an ICE, so it creates different looking wear patterns, but worth investigating a bit.

I was gonna ask my dealer to replace pads+disks...

 

[phidauex]

I was gonna ask my dealer to replace pads+disks...

I mean, you can if you want, but I don't actually think anything is wrong. Are you having problems under hard braking? Weird noises or pulling to the side?

EDIT: Not second guessing you or minimizing your experience, just trying to troubleshoot. I've played around with the braking behavior quite a bit and the car just doesn't use brakes like any other car, and even less than most other EVs.

 

[Timmy]

I have exactly the same problem, 7K miles. I checked the rear brakes on my other car (Rav 4) and they don't have anything like that.
I am not sure that's normal.

 

[pdrisgula]

I have exactly the same problem, 7K miles. I checked the rear brakes on my other car (Rav 4) and they don't have anything like that.
I am not sure that's normal.

My Mach e failed New York State inspection because the person looking at the car said this rotor wear was not normal. I have an appointment at the dealership to look at it so that will be interesting. 8,000 miles. Problem seems to be limited to driver side rear.

Sponsored