Braking in rain

[auto]

Model S 2022 Refresh, this has happened a few times now in the past month.

Light to moderate rain and pressing the brake pedal didn’t do anything. Car doesn’t slow or stop. I use regen braking 95% of the time and the brake pedal is used in case of emergency stopping.

In one example, it was raining lightly and as I approached the intersection the light turned yellow. I knew regen wouldn’t stop the car in time so I applied the brakes but the car didn’t slow, kept coasting with slight deceleration due to regen. I had to step on the gas pedal to zip through the intersection and cross.

Second example was on the highway, I sped up in the fast lane and another car entered my lane requiring me to step on the brakes. Again nothing happened but thankfully regen started slowing the car.

The car is <2 years old and I can’t imagine brakes are going out already. Is this a known problem? Should I open a service center ticket for this?

 

[ucmndd]

This is typically the sensation that occurs when the anti-lock braking system is engaged.

Be a little less stabby on the brakes during those “emergency stopping” cases you reference. There is a lot less friction available from the tires when it’s wet out, particularly if you’re on 21s with summer tires. The brakes can work just fine but if the tires have no traction you aren’t stopping in any case.

 

[auto]

I don’t believe I’ve been any more “stabby” than what I’d expect for emergency braking. This wasn’t a “slam the brakes” moment, it was a “better use the regular brakes, oh oh they’re not working” moment. Interestingly the brakes seem to work ok after the initial scare so it’s almost like they don’t work when I need them but if I try braking again with the same intensity they work fine.

Also I’m in Toronto, Canada so this time of year the car has winter tires on with more grip than the summers.

I’ve had the car two years and only seem to have noticed this in the last couple of months (only when raining although not sure I want to experience this in real winter weather with sleet and snow).

 

[beatle]

Sounds like you had rust on the rotors.

 

[MFrunkerOG]

Happens to me as well. When it’s damp outside, I just brake a bit when I start driving to get the moisture off the rotors / pads and then all is fine after.

 

[Dangerous Fish]

Yes, probably wet rotors giving the sensation the brakes aren't working. They are, you just need to press them harder than you usually would.
There's supposed to be a water-clearing system on Teslas which applies brakes very slightly every now and then to clear the water.

I had the same issue on the last ICE car I owned (BMW 330). That was also supposed to have a water clearing system, but it didn't work well/at all and often I'd find after several miles of not using the brakes on a rainy day, when I suddenly had to use them they weren't there!

But check the condition of your rotors anyway as if you seldom use the brakes they could be corroded and need a clean up which will always improve braking efficiency.

 

[fholbert]

Model S 2022 Refresh, this has happened a few times now in the past month.

Light to moderate rain and pressing the brake pedal didn’t do anything. Car doesn’t slow or stop. I use regen braking 95% of the time and the brake pedal is used in case of emergency stopping.

In one example, it was raining lightly and as I approached the intersection the light turned yellow. I knew regen wouldn’t stop the car in time so I applied the brakes but the car didn’t slow, kept coasting with slight deceleration due to regen. I had to step on the gas pedal to zip through the intersection and cross.

Second example was on the highway, I sped up in the fast lane and another car entered my lane requiring me to step on the brakes. Again nothing happened but thankfully regen started slowing the car.

The car is <2 years old and I can’t imagine brakes are going out already. Is this a known problem? Should I open a service center ticket for this?

If that was happening to me I’d park the car before you kill yourself or worse, someone else. I not going to knowingly drive a car without brakes.

Now that you’ve posted this on the internet. If you have an accident and some lawyer sees this, you’re going to get sued and you won’t have a leg to stand on.

Having a receipt that Tesla had fixed the brakes would really help your case.

 

[auto]

Car is in service with Tesla and they recommended brake clean (said it should be done once a year every 20,000km). They think it’s likely corrosion and said it’s common given regen does most of the braking and manual brakes aren’t used regularly. $300 fee for the service.

For the lawyers that are reading this, I did my part

 

[auto]

Update- Tesla took apart and serviced brakes and noted rear slider pin was siezed. I imagine this was contributing to the issue.

They also noted I have wrong sized tires and to replace for optimal performance as car is setting output based on expected size. I have winter tires 245 19in and they’re saying it should be 255 front and 285 rear. I think my summer tires supplied by Tesla are the recommended size.

 

[Dangerous Fish]

Update- Tesla took apart and serviced brakes and noted rear slider pin was siezed. I imagine this was contributing to the issue.

They also noted I have wrong sized tires and to replace for optimal performance as car is setting output based on expected size. I have winter tires 245 19in and they’re saying it should be 255 front and 285 rear. I think my summer tires supplied by Tesla are the recommended size.

What wheels are the 245 winters fitted to?

 

[uniqrenders]

In such cases, you need to contact the service, because this is fraught with consequences