Hard Braking in Snow

[SteveWilkins]

Hey Gang,

This is my first post! I recently picked up a 2018 P100D, which I love. I have had a few issues, including the MCU issue/recall, but recently I have been having a problem with braking.

In a scenario where I have just started driving, and we have fresh snow, the brake pedal is extremely hard, and the car will not stop properly. It almost feels as though there is ice that's built up between the pads and rotors, but that doesn't explain the hard pedal feel. Has anybody else run into this?

Steve

 

[beatle]

Did someone fill your brake fluid reservoir with water? Could also be your pads seizing in the calipers. A 2018 is pretty new, though you are in Vermont. My car came from Chicago and the front brakes were mostly seized after 4 years.

 

[bishoppeak]

Could be the ABS is cycling and that is effecting the pedal feel

 

[thebishop]

I have a much older car, but got my breaks replaced by Tesla to some “winter package” as they worked crap during winter. Made the car new. Maybe someone else knows the difference (might be that you car already has such ones from factory).

 

[pabla]

It’s the ABS system, basically what’s happening is the cars detecting slip and not allowing for more braking instead, it’s pumping the brakes in a sense because that will slow you down quicker. That’s the case with my other ICE cars too

 

[beatle]

To test whether it's ABS/traction limited, can you get to an area with better traction and test? If the problem goes away, you can toss the idea that the braking system has bad fluid or frozen pads (though I'd still encourage people to lube their pads and calipers annually).

 

[SteveWilkins]

It’s the ABS system, basically what’s happening is the cars detecting slip and not allowing for more braking instead, it’s pumping the brakes in a sense because that will slow you down quicker. That’s the case with my other ICE cars too

Is this true even if the car is not slipping/sliding? I should be clear - in the scenario which I initially described, the car is not sliding.

 

[SteveWilkins]

I have a much older car, but got my breaks replaced by Tesla to some “winter package” as they worked crap during winter. Made the car new. Maybe someone else knows the difference (might be that you car already has such ones from factory).

Interesting! Do you have any more info on this? Was it through Tesla? My car already has the winter package, but maybe you went with something aftermarket?

 

[SteveWilkins]

Did someone fill your brake fluid reservoir with water? Could also be your pads seizing in the calipers. A 2018 is pretty new, though you are in Vermont. My car came from Chicago and the front brakes were mostly seized after 4 years.

I guess anything is possible! Definitely worth checking out. I will take a look this weekend.

 

[Jughead135]

Is this true even if the car is not slipping/sliding? I should be clear - in the scenario which I initially described, the car is not sliding.

Well, is it "not sliding" because the ABS is doing its job? The ABS computer senses wheel lockage--ideally before it actually happens to the degree that a human can sense it--and releases enough of the braking action to allow the wheel to turn (instead of locking, at which point the car's momentum will cause it to slide on the ice, etc.).

 

[SteveWilkins]

Well, is it "not sliding" because the ABS is doing its job? The ABS computer senses wheel lockage--ideally before it actually happens to the degree that a human can sense it--and releases enough of the braking action to allow the wheel to turn (instead of locking, at which point the car's momentum will cause it to slide on the ice, etc.).

It's not the ABS coming on. I have tracked many cars and am familiar with the typical nannies. This is different, in that its just a very hard pedal feel, with no slowing of the vehicle.

 

[pabla]

I guess your best bet in this situation is like @beatle suggested is to go on a dry patch of road and try emergency braking and seeing if you experience the same thing, if you do then its definitely not ABS and something maybe wrong with your brakes. Since EVs use their brakes very little the calipers can seize if not maintained correctly so that also could be what is happening. To me it just sounds like ABS doing its job as Ive experienced the same exact thing in my Model S and other ICE cars only in low traction environments

 

[thebishop]

Interesting! Do you have any more info on this? Was it through Tesla? My car already has the winter package, but maybe you went with something aftermarket?

I got it through Tesla - see attached screenshot. At earlier models they also switched to different rotors - but my car already had those. Done March 2018.

 

[thebishop]

It's not the ABS coming on. I have tracked many cars and am familiar with the typical nannies. This is different, in that its just a very hard pedal feel, with no slowing of the vehicle.

That is how mine felt before the updated pads/front rotor.