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Suddenly no brakes today...

RJUK

Member
May 31, 2019
58
8
United Kingdom
Hi folks,

I drove my car yesterday in and out of work as usual, all fine. Then this morning I get in to drive to work and the brake pedal is very soft indeed, as I press it to shift into drive. The pedal goes down way more than usual.

I start driving, cautiously, but it's much the same scenario - brake pedal going down much further than usual and no firmness to it at all, very mushy indeed, almost no brakes, though at the very bottom of the pedal they do work, to a degree.

I limp on to work, as it's only a short distance and I mostly use regen anyway, and notice that the brake pedal doesn't return after being pressed, until I touch back on the throttle.

Called Tesla when I got into work and they told me to do a soft reset (no difference) and then told me to turn the car off for 10 minutes and sit inside, then after 10 minutes try again... it initially felt firm, but 2nd press and it went back to mush.

I can't see any fluid inside the wheels to indicate a leak at any of the calipers and I checked the brake fluid reservoir, but it looks to be plenty full and no visible leaks at that end, either.

I've now been sat on hold for the customer service specialist for over 35 minutes... my local SC told me to ring the emergency support and they told me to speak to a specialist... so I've spent half the day on hold with Tesla. Must be a lot of issues that people are having...

Anybody else had a similar issue? My car is a M3P.
 

m3p_uk

Member
Aug 1, 2019
623
160
UK
Sounds like an air bubble somewhere or lack of fluid.
Try pumping the brake pedal a few times and see if thats any better?
 

Glan gluaisne

Supporting Member
Sep 11, 2019
2,782
2,700
UK
I believe the braking system uses an electric pump that augments the pressure applied to the calipers, along with electrically operated multiple valve system to control the actual fluid pressure applied to each caliper (for the equivalent of ABS/stability control/etc). As a fail safe, the system should revert to allowing the pedal to directly pressurise the system, but when this happens it should be apparent by a change in the pedal feel and also by some indication that something in the system has failed.

There is also part of the system that allows the pedal to provide augmented regen, rather than friction braking, initially, and changes the pedal feedback to make the initial pedal movement feel the same as when the friction brakes are operating, I believe. Perhaps this feedback system has developed a fault?

It sounds almost as if there has been some sort of pump or valve failure, but one which the car hasn't detected. Given that, I believe, it's a mandatory requirement that any fault in the braking system needs to be indicated to the driver, I wonder quite how this has happened without there being any such indication?
 
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Reactions: ACarneiro

RJUK

Member
May 31, 2019
58
8
United Kingdom
I believe the braking system uses an electric pump that augments the pressure applied to the calipers, along with electrically operated multiple valve system to control the actual fluid pressure applied to each caliper (for the equivalent of ABS/stability control/etc). As a fail safe, the system should revert to allowing the pedal to directly pressurise the system, but when this happens it should be apparent by a change in the pedal feel and also by some indication that something in the system has failed.

There is also part of the system that allows the pedal to provide augmented regen, rather than friction braking, initially, and changes the pedal feedback to make the initial pedal movement feel the same as when the friction brakes are operating, I believe. Perhaps this feedback system has developed a fault?

It sounds almost as if there has been some sort of pump or valve failure, but one which the car hasn't detected. Given that, I believe, it's a mandatory requirement that any fault in the braking system needs to be indicated to the driver, I wonder quite how this has happened without there being any such indication?

Thanks for this. My car is around 9 months old now, so I doubt there's any air in the system and there's no sign of a leak anywhere (plus brake fluid reservoir is still full).

I think you're right in that something mechanical is faulty - I was thinking maybe the ABS pump or similar...

Anyway, car has now been taken away on a low loader, so that's for Tesla to figure out. I guess I'm lucky that it was apparent from the minute I got in the car and pressed the brake pedal. Had I been going on a long journey I could have opted to quit right there.

As work is only around 5 miles away and I use mostly regen normally anyway, I opted to push on to work and see if using the brakes brought back any feel, whilst driving cautiously. When loading the car onto the recovery vehicle the recovery chap (who does a lot for Tesla due to having a great low-loader truck for low vehicles) confirmed that it definitely wasn't right. (Not all in my head!)
 

JS77

Member
Nov 24, 2019
95
64
England
Thanks for this. My car is around 9 months old now, so I doubt there's any air in the system and there's no sign of a leak anywhere (plus brake fluid reservoir is still full).

I think you're right in that something mechanical is faulty - I was thinking maybe the ABS pump or similar...

Anyway, car has now been taken away on a low loader, so that's for Tesla to figure out. I guess I'm lucky that it was apparent from the minute I got in the car and pressed the brake pedal. Had I been going on a long journey I could have opted to quit right there.

As work is only around 5 miles away and I use mostly regen normally anyway, I opted to push on to work and see if using the brakes brought back any feel, whilst driving cautiously. When loading the car onto the recovery vehicle the recovery chap (who does a lot for Tesla due to having a great low-loader truck for low vehicles) confirmed that it definitely wasn't right. (Not all in my head!)

Did Tesla arrange for the low loader or was it through Green Flag/RAC? Sorry to hear, hope it gets fixed soon
 

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