Front brake disc problem

[jasrocha]

Hi,
I have a Leaf with 1 year old and 15500km,
the 2 front brake discs don't have use marking on the all disc,
it appears that the brake pads don't touch fully on the disc, only in the center most area.
Can anyone help me troubleshooting this?
Attached photo.

[dmacarthur]

My personal take on those brake pads is that this is not a concern. The pads get light use anyway because (ideally) most of the braking is done by regeneration, so mostly these rotors are just going round and round. As for the little pitting on the outer parts, that simply happens to rotors when they get wet or are in contact with road salt. If your car is stopping fine under heavy braking (which I suspect it does) then, as they say, not to worry.

[Drew21]

I think we need additional information to provide useful advice.
1) Can you confirm if the Leaf is one year old with 15K km or if you have had the car for one year and it is older?
2) Do all four brake rotors have rust pitting or only the one you took a picture of? Does the back side of the rotor(s) look the same?
3) How often is the Leaf driven, or conversely how long does it sit parked? Where does it sit when parked: garage, outside, close to the ocean? Do you wash the car regularly?
4) What are your driving conditions: highway driving with minimal brake use or stop-and-go traffic with lots of stopping and starting? More importantly, do you fully engage the (mechanical) brakes regularly?
5) Most importantly, do you feel like the brakes are operating correctly or do you have trouble slowing the car?

As the previous poster noted, disc rotors do get a light coat of superficial rust when sitting, which will be scrubbed off the next time the brakes are engaged. If a car sits for an extended period and/or is parked in more corrosive environments (e.g., next to the ocean) you would expect to see more rust on the rotors.

I would not expect to see rotors with rust pitting on a new car (to me a one year old, 15K km car is new). Without more information about your operating conditions I can only speculate about what's going on, but the pitting suggests that your brake pads are not fully engaging with the outer portion of the rotors. This could be caused by sticky calipers or a misalignment of the pads.

The first thing I would do is really engage the brakes a few times, obviously in a safe location. Get up to road speed and do a controlled emergency stop. Do it a couple more times for fun. Is the entire rotor now clean and shiny (except for the pitting)? If so I would keep monitoring the situation (does the rust come back or get worse?) but probably wouldn't worry about it too much. If not you can ask for more advice here or get your brakes looked at by an expert to make sure all the moving parts are properly lubed and your brakes are functioning correctly.

[denwood]

On that note (doing a few hard stops), you'll work the pads a bit harder if you charge to 100% first...no regeneration will be at play this way.

If you use ePedal a lot, the pads will likely never get worked too hard. I'd also pull the tires off and do a brake service. Lube the pins and pad contact areas. If you're in salt air (near the Portugese coast?) , you'll want to do this once a year.

I also like to check rotor temps with an infrared (point and shoot) temp gun after a few hard stops if you suspect any brake issues. Check that front right and left match, and that rear left right match. The rears will be cooler than the fronts. If they are not close (right vs left), you've got a brake issue.

[jasrocha]

Hi,

Thanks for the help.

To Drew21:
The car is from april/2021 as now 17332km.
Only the 2 front brakes have the issue, the rear brakes use the full disc. (see pic)
I drive all days more/less 50km - 90km.
Its parked outside. Very far the ocean. 1 wash 2 mouths.
Its a small town, stop and go and some fast road about 40km.
I rarely use the e-padal, prefer mode B and brake pedal.
The braking fells OK.

My concern its never seen any Leaf like this, I now look for every one I see on the rood and new ones.
My curiosity it's not rust, it's why doesn't disappear when braking like in the center most area and like in the rear discs and like in the other cars?

To test I made a paint marking on the disc and did some heavy braking and braking on normal day, and it
like you can see on the photos, don´t clean the paint.

FRONT PAINTED DISC:

mapbox geojson

REAR DISC:

[Drew21]

OK. There is definitely something wrong with your front brake pad engagement.

Can you return to the dealer where you got the car? This definitely seems like an issue that should be fixed as soon as possible. I've never had anything resembling a new car or visited a car dealer, but I would hope that they will fix this for free for you.

Good luck.

[LeftieBiker]

It looks to me like the previous owner ran the pads down to bare metal, then did a panic stop on it for good measure. Then, I'm guessing the dealer just put new pads on it.

[Drew21]

The OP indicates that the car is one year old with 17,xxx km, so it seems unlikely that the pads could be severely worn through use or negligence or that they would have been replaced.

Regardless, the OP should take the car to the dealer or a trusted mechanic so that the brakes can be examined in person.

[LeftieBiker]

I should have read back farther - I saw a reference to a dealer, and drew the conclusion that I posted. My bad.

[alozzy]

I'm not sure about newer LEAF's, but if the brake calipers have dual pistons then most likely the top piston is stuck and not applying enough pressure. Replacing the brake caliper would resolve that.

The brake caliper carrier could also be super rusty, so the pads aren't bottoming out properly (askew).