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Parking Brake
- Thread starter Maka344
- Start date
Tevo Solutions
Former Vendor
AFAIK nobody has actually demonstrated or proved what the long press does vs. the short press. It's all been speculation so far...
Tevo Solutions
Former Vendor
"Everyone in agreement" is not what I strive for as it's impossible.
Just explaining something accurately and completely is all I can hope to do. There will always be those who don't agree for whatever reason. Often just to be difficult or because they can't admit they might be wrong.
PARK in a Tesla is not like PARK in an automatic transmission car. Teslas don’t have a parking pawl in the gearbox.
Pressing PARK while stopped will apply the rear brakes, which are actuated with an electric motor, and the car displays “P”. In older cars, this was done with a separate caliper from the service brakes. This is how you will normally park your car.
Holding PARK while stopped will apply additional force to the parking brakes and turn on the parking brake light. You may want to do this on a steep hill where the normal PARK mode’s clamping force might not be enough to hold the car in place… kind of like giving an extra pull on a conventional parking brake handle.
Holding PARK while moving will apply the parking brakes temporarily, until you release the button. You might want to use this if there is a problem with your service brakes. Some might refer to this as the emergency brake function.
This has been discussed before in the Model 3 and Y forums. There is no difference in functionality between regions.
Hope this helps.
Pressing PARK while stopped will apply the rear brakes, which are actuated with an electric motor, and the car displays “P”. In older cars, this was done with a separate caliper from the service brakes. This is how you will normally park your car.
Holding PARK while stopped will apply additional force to the parking brakes and turn on the parking brake light. You may want to do this on a steep hill where the normal PARK mode’s clamping force might not be enough to hold the car in place… kind of like giving an extra pull on a conventional parking brake handle.
Holding PARK while moving will apply the parking brakes temporarily, until you release the button. You might want to use this if there is a problem with your service brakes. Some might refer to this as the emergency brake function.
This has been discussed before in the Model 3 and Y forums. There is no difference in functionality between regions.
Hope this helps.
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Presumably something like this one from the Owners Manual:Funny how this question keeps popping up with no definitive answer.
We'll have the answer for you all in a couple of weeks time.
The short press puts on a grey "H" light, the long press puts on a red "P" light.
That about covers it I think!
WannabeOwner
Well-Known Member
Same as the "Hill Hold" symbol? That can be activated by pressing the Brake Pedal hard.
The short press puts on a grey "H" light, the long press puts on a red "P" light.
That about covers it I think!
A short press puts it in PARK. The H symbol is the auto hold function.
Hold mode using the Bosch iBooster 2 to apply and hold the main service brakes. It has nothing to do with the parking brakes.
I looked at this in some detail a year or so back and it's me referenced ealier in the thread who accidentally applied the emergency brake whilst driving - oops.
I always used to apply the parking brake when stationary (P symbol and whirring actuator noise) but now I only use that when on a hill. I also don't put the car into park when I've finished reversing into my drive - just apply the footbrake, unbuckle and get out. The car doesn't complain and I guess that removing your seat belt and opening the door does the job anyway. I'll check the sequence in more detail next time I drive it and maybe I should be engaging park when I stop
I always used to apply the parking brake when stationary (P symbol and whirring actuator noise) but now I only use that when on a hill. I also don't put the car into park when I've finished reversing into my drive - just apply the footbrake, unbuckle and get out. The car doesn't complain and I guess that removing your seat belt and opening the door does the job anyway. I'll check the sequence in more detail next time I drive it and maybe I should be engaging park when I stop
Not disagreeing, but Tesla must know what it does.
Not a rep, Tesla engineers via the manual or some other official method.Thought you just said not to trust a Tesla rep
See also the Tesla video above that states the parking brake is applied automatically when put in park. No need to do the long press to get the car to apply the brakes. The question mark seems to be around what additionally does the long press do to the already activated parking brake. Some say it give you extra force - some say no difference. Really hard to measure.
Incidentally to the people getting out of the car without putting it in park, the manual warns against doing this.
I tried that twice this morning and the pedal didn't move at all. But we all know that Teslas don't all respond the same, see auto wipers for example.
I knew what you meant, I was teasing.
The key question is indeed what is that extra noise on a long press. The manual doesn't answer that specific question. We are really discussing an engineering / design question.
Realistically it's an edge case anyway, I am not suggesting a single press is in someway less safe.
I think everyone agrees there is an additional sound on a long press even after a short press.
ACarneiro
Active Member
This discussion has been had multiple times on all the model sub-forums and for good reason - the manual is overly simplified, and does not clarify the physical difference between the two modes clearly, which blows the whole thing open to speculation.
Here's my understanding based on various teardowns I've seen on the brake assembly for the model Y and the model S from trusted sources like Munro and from other informed users on here:
So TLDR;
Here's my understanding based on various teardowns I've seen on the brake assembly for the model Y and the model S from trusted sources like Munro and from other informed users on here:
Park - (single push, with vehicle stopped and foot on brake) disengages any drive and uses “hill hold” (basically keeps the motorised brake booster engaged - which is what AP/FSD uses to slow the car just like your foot would) so the car is stationery, and you don’t hear anything because the brakes are still engaged as they were when your foot was on the pedal. When you get out of the driver seat, the brake booster resets to its default position and the electric parking brake (rear wheels only) engages automatically.
Emergency brake - (long push and hold) is intended for emergency stops, and would add the electric parking brake into the mix in addition to what the hydraulic brakes are doing if they're functional. This is primarily for emergency situations for exactly the same reason other automatic cars will let you apply the handbrake for emergency situations… it could save you a change of pants if you lose your hydraulic brakes for whatever reason.
Pushing and holding the emergency brake when in park is just activating the parking brake before you leave the drivers seat. It is not adding extra braking force, because the brake booster will reset as per the default use case and the light in the dash will go out as usual. The light is just there to tell you why you are rapidly decelerating or hearing a horrendous noise if you push and hold the button by accident
To add some clarity for those who are confusing the two braking systems on these cars:
The electric parking brake is an entirely separate system to the standard hydraulic brake system on all four corners. This is true of all current models, it's a standard safety feature - you can't not have a redundant system for braking.
The hydraulic brake system is the same as most other automatics, aside from the fact that the newer models use the Bosch I-booster, which allows AP/FSD to use the hydraulic brakes with no vacuum available (or needed) for a traditional booster.
Applying the parking brake manually when parked does nothing but apply the parking brake before you leave the vehicle. It does not "apply extra pressure", because that's not a thing with electric parking brakes, they're on or off, and apply a standard force based on the potential loaded weight of the vehicle. In any case, with parking brakes, unless they're just not functioning at all, the grip level from the tyre will always be your first point of failure. It's not difficult to lock the rear wheels completely on modern brakes. It does give you peace of mind if parking on a hill however that the transition between the two braking modes which happens by default does not cause the car to roll unexpectedly (but again - the parking brake would catch the car eventually, but this could still cause someone a fright, or to slip).
So TLDR;
- Parking brakes are independent of the hydraulic brakes on ALL cars - for good reason
- Putting the parking brake on manually before you get out does not apply extra braking pressure - it still only applies to the rear wheels (watch any video of Tesla's sliding down frozen driveways - the fronts roll, the rears slide) but it does help ensure the transition between the hydraulic brakes and the parking brake doesn't cause issues on steep hills if you so choose
- There is no way of parking and leaving the vehicle with all four wheels braked - hence the safety advice that you should never park on a hill when traction is compromised
But go and try a single push now, after driving back or forward. You will hear something, you hear a whine noise for a second. You suggest there is nothing to hear on a single press?
I just tried this now...
Car parked and changed into drive, I hear whine noise. I drove forward a few feet. I remain in the drivers seat. Single brief push, I hear a whine noise from rear wheels. I press and long hold, I hear another clunk/knock noise.
If you don't, then cars seem to be behaving differently.
I do have my car set to stopping mode hold, if this is making a difference.
Assuming you're not doing this from neutral but is your foot fully on the brake when you press park? You're probably just hearing the brake booster? Maybe it's a bit noisier than mine, I can barely hear anything even when I'm listening for it.. but then mine has less than 1k miles on it currently
Logically the clunk noise would be the parking brake. Again maybe yours is just louder through use or something.
