Discuss: Tesla has an Emergency Brake: Here's how to use it

[Not a Tesla App]

While it's not obvious, all Tesla vehicles include an emergency or parking brake. This could be useful when parking on a hill, steep incline, or as a back up i… Read More

Tesla has an Emergency Brake: Here's how to use it

By Emergency Braking, I’m not talking about Tesla’s built in Collision Avoidance. This Emergency Brake can be used when parking on a hill or other steep i

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[SoMEtesla]

Teslas don't have a parking pawl like cars with automatic transmissions. Putting the car into "Park" causes the electric motors on the rear brake calipers to push the caliper pistons against the pads. This differs from the hydraulic actuation caused by pressing the brake pedal. If the car is moving when "park" is selected the request will be ignored. Holding the "Park" button/icon for an extended period of time (more than a tap) will cause the parking brake to be applied regardless of the speed of the vehicle.

 

[joe_apxc]

Holding the "Park" button/icon for an extended period of time (more than a tap) will cause the parking brake to be applied regardless of the speed of the vehicle.

Is this a "safe" thing to use in emergencies where the brake from the pedal does not work anymore? Is it even useful? You loose about a second or whatever the period is that is considered "an extended period of time" for the car to apply the parking brake. And what is the actual difference when you double tap park when standing still? I can see an additional red icon saying ((P)) but i cant hear anything applying apart from the usual parking brake when pressing P once instead of twice.

 

[SoMEtesla]

Is this a "safe" thing to use in emergencies where the brake from the pedal does not work anymore? Is it even useful? You loose about a second or whatever the period is that is considered "an extended period of time" for the car to apply the parking brake. And what is the actual difference when you double tap park when standing still? I can see an additional red icon saying ((P)) but i cant hear anything applying apart from the usual parking brake when pressing P once instead of twice.

In a traditionally designed car you would need to either move your foot or arm to the parking/ebrake actuator and apply it. I don't think tapping the end of the stalk is much different. The electrically actuated brake turns a screw which applies mechanical force against the piston which in turn pushes against the brake pads. Total failure of the normal hydraulic brakes would involve jamming of the master cylinder/pedal or a leak in the hydraulic system. Neither of these failures would affect the E brake actuation so I would say it is safe. I actually don't believe the double tap does anything more than entering park mode besides the icon on the screen. It may be there to give us a setting we are used to in traditional cars. Pushing a automatic transmission into park while moving at more than a crawl will at best result in the pawl being ground into small pieces with little braking effect so that is not much of a backup. The only real concern to me is the fact that we have only the parking brake to hold the vehicle when left alone. There are two brake calipers that are actuated so there is some redundancy. An automatic trans and standard differential equipped car need only have poor traction on one of the wheels on the driven axle to start moving on its own if its parking brake is not applied.

 

[joe_apxc]

In a traditionally designed car you would need to either move your foot or arm to the parking/ebrake actuator and apply it. I don't think tapping the end of the stalk is much different. The electrically actuated brake turns a screw which applies mechanical force against the piston which in turn pushes against the brake pads. Total failure of the normal hydraulic brakes would involve jamming of the master cylinder/pedal or a leak in the hydraulic system. Neither of these failures would affect the E brake actuation so I would say it is safe. I actually don't believe the double tap does anything more than entering park mode besides the icon on the screen. It may be there to give us a setting we are used to in traditional cars. Pushing a automatic transmission into park while moving at more than a crawl will at best result in the pawl being ground into small pieces with little braking effect so that is not much of a backup. The only real concern to me is the fact that we have only the parking brake to hold the vehicle when left alone. There are two brake calipers that are actuated so there is some redundancy. An automatic trans and standard differential equipped car need only have poor traction on one of the wheels on the driven axle to start moving on its own if its parking brake is not applied.

Thanks for clarifying! I thought of the last argument too. If the parking brake fails, theres nothing else stopping the car from rolling down a hill like we have in traditional manuals where when leaving it in any gear (except Neutral of course), it will stop the car in case of parking brake failure. But i guess they thought of this at tesla in some way, otherwise we would have read about failures that happened