PARKING BRAKE--EMERGENCY BRAKE. HOW DOES IT WORK?

[BobX]

Folks: My 2017 X has the separate caliper for I am not sure what. When one pushes the park button, the car shifts into park. What does that activate? Is it the same mechanism that "holds" your vehicle at a stoplight (whatever that is)? Does it activate the small electrically controlled caliper? When shifting into park, all you get on the instrument panel is "P". However, if you press and hold the park button, then the parking brake icon comes on. Presumably that is the small caliper activated. So if putting the car into park is activating the emergency/parking brake caliper, why doesn't the parking brake icon illuminate on the instrument panel. Prior to acquiring the X, my only experience is with ICE cars---auto transmission shift in Park, that's it. Rarely use the parking brake. Among other things, I want to understand if the parking caliper is getting any "exercise". If it isn't I suspect that there is a good chance it will seize. particularly with our snow/salted roads all winter. That's what always happened to my ICE cars through lack of use. I plan on brake maintenance this spring and am trying to understand if disassembly of the parking brake caliper is required.

Thanks to all that respond.

 

[LoudMusic]

I'm actually curious to know as well.

I *think* the Hold feature is electrical wizardry with the motors, as I don't hear anything mechanical when it engages/disengages. And Park is just using the brakes. But I don't know what the Emergency Brake engages and a quick internet search didn't show me anything.

This is all coming from my experience in my Model Y.

 

[bo3bdar]

There are actually several levels there. There are some threads here regarding this, but I don't feel like searching for them at the moment. This is for Model 3- I'm not at all certain this applies to Model X.

Regular brakes. Using just foot pedal, and uses the hydraulic brakes and calipers.

The Hold operation does not use the parking brake, but it does use the regular brakes.

The Park brake is the one touch on the button on the right stalk, and does activate the calipers for the back wheels. You hear this whining noise as it activates. It's a worm-screw gear that activates, and it's a separate mechanism from your normal hydraulic brakes. You should use this all the time and get in the habit of pressing that button. A couple of people have had roll-away accidents by being sloppy about this. Generally it will also auto-activate if you try to get out of the car while in D, but there are scenarios where it doesn't happen.

The Parking brake is the press and hold on the stalk, and would be equivalent to the emergency brake on a regular car. You can and should activate this at speed if you are having an actual emergency. Same as engaging when parked, press and hold. From what I've read this uses the same worm-screw gear for the Park brake, but runs the motor longer for higher pressure on the pads, and better braking. As far as I know the Parking brake uses the same caliper pads as the regular brakes, but is activated by that worm-screw motor instead of hydraulics.

I'm fairly sure there is not a secondary pad/drum for the parking brake. I would have gone to look this up on the schematics- but Tesla is hostile to the owners and forced them to take it down, because apparently we shouldn't be allowed to know how our cars work. We need a Right to Repair Law so that we can understand how it all works without Tesla just telling us to not worry our pretty little heads about it. They say nothing about how it works in the manual.

 

[BobX]

I am warming to the concept as LoudMusic points out, it is just magic and a magician never reveals the secret to their tricks. That is how I feel on the short and long press!!!!! On the Model X, the parking brake caliper is seperate from the brake caliper. I have read elsewhere about pressure differences on the brake caliper for short and long presses. But it doesn't make sense to me. Why would a manufacturer do that? If light pressure is applied to the parking brake, what happens if you are parked on a hill? Will the light pressure hold the car? Does the car know you are parked on a hill? I have not seen any documentation from Tesla regarding parking on a hill. I am of the view now that Models X's have a parking pawl (similar to those in the auto trans of an ICE car). I only say this because I read that the Model 3 DOES NOT have a parking pawl. So I conclude that the X DOES have a parking pawl. If that is the case then the X operates like a regular ICE car--engage the parking pawl when parking, but use the Parking brake if on a steep hill so as not to "stress" the parking pawl. Consider me crazy if you like. Comments?