Bleeding Brakes

[Taycan-Gentian]

This is incorrect. Regen and mechanical braking systems aren't completely decoupled, even within the threshold of regen only while depressing the brake pedal. Every time you step on the brake pedal, you're moving fluid within the master cylinder. How do you explain the force pushing back against your foot when braking?

Apologies in advance, but the general "that's just how it is" conclusion is lazy, and for car owners who look to this forum for advice, end up living with a suboptimal, sloppy car.

Edit* If you haven't already done so, get the PSM update (which includes a full brake bleed) https://static.nhtsa.gov/odi/tsbs/2024/MC-11007026-0001.pdf

If you're still unsatisfied, then well yea...that's just how it is

Thanks mate - I will.have a chat with Porsche.

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[TonyR]

This is incorrect. Regen and mechanical braking systems aren't completely decoupled, even within the threshold of regen only while depressing the brake pedal. Every time you step on the brake pedal, you're moving fluid within the master cylinder. How do you explain the force pushing back against your foot when braking?

Apologies in advance, but the general "that's just how it is" conclusion is lazy, and for car owners who look to this forum for advice, end up living with a suboptimal, sloppy car.

Edit* If you haven't already done so, get the PSM update (which includes a full brake bleed) https://static.nhtsa.gov/odi/tsbs/2024/MC-11007026-0001.pdf

If you're still unsatisfied, then well yea...that's just how it is

You’d better contact Porsche to let them know they don’t know how their brakes work.

https://christophorus.porsche.com/en/2022/403/technique-taycan-energy.html

The Taycan is brake by wire - the pedal is not connected to the master cylinder but to a computer that works out how much regen and how much mechanical braking is needed. So the brake pedal feel has nothing to do with the hydraulic systems status but with a software force feedback system much like you get in some games controllers..

”The reason for this is that while the brakes are controlled by hydraulic master cylinders, those cylinders, unlike internal combustion powered cars, are not directly connected to the brake pedal. Instead, the Taycan uses what is known as “Brake by wire,” in which that dedicated braking computer calculates the amount the pedal has been depressed, and according to Porsche themselves, 90% of the time, the electric motors are producing enough decelerative force to effectively brake the car.”
https://www.stuttcars.com/braking-porsche-the-technology-of-the-taycan-evs-braking-system/

 

[mystermykee]

You’d better contact Porsche to let them know they don’t know how their brakes work.

https://christophorus.porsche.com/en/2022/403/technique-taycan-energy.html

The Taycan is brake by wire - the pedal is not connected to the master cylinder but to a computer that works out how much regen and how much mechanical braking is needed. So the brake pedal feel has nothing to do with the hydraulic systems status but with a software force feedback system much like you get in some games controllers..

”The reason for this is that while the brakes are controlled by hydraulic master cylinders, those cylinders, unlike internal combustion powered cars, are not directly connected to the brake pedal. Instead, the Taycan uses what is known as “Brake by wire,” in which that dedicated braking computer calculates the amount the pedal has been depressed, and according to Porsche themselves, 90% of the time, the electric motors are producing enough decelerative force to effectively brake the car.”
https://www.stuttcars.com/braking-porsche-the-technology-of-the-taycan-evs-braking-system/

Thanks for the find. I stand corrected!

However, to generalize a spongy feel on that's just how it is, again, is lazy. An improperly bled system, especially pre PSM update, during normal braking all the way to a complete stop, can feel spongy.

 

[TonyR]

Thanks for the find. I stand corrected!

However, to generalize a spongy feel on that's just how it is, again, is lazy. An improperly bled system, especially pre PSM update, during normal braking all the way to a complete stop, can feel spongy.

The feel in a Taycan has nothing to do with bleeding the hydraulic brakes. The brake pedal is connected by a wire to a computer not the hydraulics. The feel is defined in software and is similar to other ICE Porsches with direct hydraulic brakes IME. My Cayman for example feels similar and it’s not because the brakes need bleeding. It’s serviced by an independent that preps Porsches for professional racing.

 

[Shug]

To answer the OP original question, "I have had my Taycan for a few weeks, and notice that the brakes feel a little spongy."

My brakes were spongy after a recall where the front brake hoses were replaced. My guess is that air was somehow introduced during the procedure.

A second visit to Porsche and they bled the front and rear brakes; all sorted with a nice pedal feel again.

My interpretation is that under normal driving, a closed electronic isolation valve traps fluid in the emulator loop to create the simulated pedal feel during regen. The braking system diverts fluid directly to the physical brake calipers when the maximum regen is insufficient to slow the car.

Asking for your brakes to be bled including the ABS system is never a bad choice.

 

[Taycan-Gentian]

Hey guys,

So had a good drive today. The spongy feel seems to be at low speeds, 5mph and under.

The brake pedal changes from feeling solid, then as your speed comes down and you head below 5mph the feel just changes and becomes spongy.

I am assuming this is when the braking system switched from regen to regular brakes? And I assume the hydraulic brake system needs bleeding.

It can catch you out, especially in traffic.

Thought it was interesting and worth mentioning.

Is this same for you guys? or do you feel no difference in the transition?

Cheers

 

[RAHRCR]

Hi Guys,

I have had my Taycan for a few weeks, and notice that the brakes feel a little spongy.

It had a 111 point health check by Porsche prior to me collecting it and everything on the report is good. All recalls and updates carried out.

Am I able to bleed the brakes myself the old fashioned way? Or is this braking system one that needs the dealer to use a pressurised bleeding system and the PIWIS software to achieve success?

Any ideas? Anyone bled their own brakes?

Thanks

There is nothing special about bleeding the brakes. They are essentially the same mechanically as the Panamera. The challenge is the reset. Need a tool in order to do it.

 

[mystermykee]

Hey guys,

So had a good drive today. The spongy feel seems to be at low speeds, 5mph and under.

The brake pedal changes from feeling solid, then as your speed comes down and you head below 5mph the feel just changes and becomes spongy.

I am assuming this is when the braking system switched from regen to regular brakes? And I assume the hydraulic brake system needs bleeding.

It can catch you out, especially in traffic.

Thought it was interesting and worth mentioning.

Is this same for you guys? or do you feel no difference in the transition?

Cheers

You are correct, typically the transition from regen to mechanical under gingerly braking when coming to a complete stop is around those speeds--you shouldn't have to feel like you need to put more pressure on the brake pedal after the transition happens.

 

[Taycan-Gentian]

You are correct, typically the transition from regen to mechanical under gingerly braking when coming to a complete stop is around those speeds--you shouldn't have to feel like you need to put more pressure on the brake pedal after the transition happens.

Thanks. Unfortunately, the difference in pedal firmness is quite significant, but not every time. As I mentioned previously, it could catch you out in traffic if you're not concentrating.

 

[TonyR]

Yes, the switch to mechanical brakes occurs IIRC at 3mph.

 

[mystermykee]

Thanks. Unfortunately, the difference in pedal firmness is quite significant, but not every time. As I mentioned previously, it could catch you out in traffic if you're not concentrating.

Oof. Yes, that's definitely not normal. If it's intermittent, there's definitely air in the system somewhere.

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