M5 F10 Brake system issues (update: Faulty Brake Pedal Sensor)

[singularity]

I mentioned this a few weeks ago that after 10 minutes of street racing brakes went became extremely soft and lost 80% of usual braking power until I let them cool down.

Now today I parked the car after a few hours of normal driving. The car was parked on very minor slope and I engaged the "P" parking brakes (does everyone's park brake make a whizzling sound when engaging/disengaging?). So the car was on "N" and a "P" brakes for 2-3 minutes while I was looking for the parking guard for a better spot, found the man and he asked me to drive inside on a special spot. I set to "D" and disengage "P" and see "Brake System/Tyre Pressure Monitor/Stability Control" all in red color and brakes became extremely soft again. Still drove the car for some 10 meters to a better parking spot, turned off/on and still had the failure warnings.

I'll check it again in a few hours but I'll most likely have to call BMW service to pick it up, or unpredictably drive to the service myself. Whatever it is, there are braking issues, I wonder if this played a role in that M5 crash in that other topic. Has anyone had "soft brakes" or brake system/stability/tyre monitor failures?

[Tupapison]

Hey

The whizzing sound you are talking about is the electronic parking system engaging and disengaging, its totally normal.

I have only driven my car for about 400km in the city and have never had this problem thou, my brakes are always perfect so far, no failures at all.

Keep me updated!

[singularity]

Originally Posted by Tupapison

Hey

The whizzing sound you are talking about is the electronic parking system engaging and disengaging, its totally normal.

I have only driven my car for about 400km in the city and have never had this problem thou, my brakes are always perfect so far, no failures at all.

Keep me updated!

Thanks for the reply. Good to know the parking sound is normal. The main problem about brake issues exists, if you track your car or street race be VERY VERY careful after several applications of brakes, it might go extremely soft all the way to the bottom. First of all they heat up very quickly, at least in my case.

I'll go and check if the problems still exist after the car has cooled off. Will keep you updated later today.

[Tupapison]

Well, the only problem i have about the brakes, and its not even a problem, is that if i have my foot on the brake, and activate the Parking brake, the brakes will automatically go softer, if you keep your foot on the brake and activate the P brake at the same time you can feel it.

Which is totally normal also.

Hope everything works out! Keep me updated

[Grover432]

Originally Posted by singularity

Thanks for the reply. Good to know the parking sound is normal. The main problem about brake issues exists, if you track your car or street race be VERY VERY careful after several applications of brakes, it might go extremely soft all the way to the bottom. First of all they heat up very quickly, at least in my case.

I'll go and check if the problems still exist after the car has cooled off. Will keep you updated later today.

I think several people wrote after your last post on this. Get your brake system checked. It is not normal for the F10 or any other car. It isn't a problem with the F10, but rather a problem with your car.

[Tupapison]

Originally Posted by Grover432

I think several people wrote after your last post on this. Get your brake system checked. It is not normal for the F10 or any other car. It isn't a problem with the F10, but rather a problem with your car.

This hasn't happened to me, hopefully it doesn't. >_<

[singularity]

Started the car just now, all errors and warnings gone. I'll take the car to service tomorrow or after that and update about the problem.

[clar]

Originally Posted by singularity

I mentioned this a few weeks ago that after 10 minutes of street racing brakes went became extremely soft and lost 80% of usual braking power until I let them cool down.

Now today I parked the car after a few hours of normal driving. The car was parked on very minor slope and I engaged the "P" parking brakes (does everyone's park brake make a whizzling sound when engaging/disengaging?). So the car was on "N" and a "P" brakes for 2-3 minutes while I was looking for the parking guard for a better spot, found the man and he asked me to drive inside on a special spot. I set to "D" and disengage "P" and see "Brake System/Tyre Pressure Monitor/Stability Control" all in red color and brakes became extremely soft again. Still drove the car for some 10 meters to a better parking spot, turned off/on and still had the failure warnings.

I'll check it again in a few hours but I'll most likely have to call BMW service to pick it up, or unpredictably drive to the service myself. Whatever it is, there are braking issues, I wonder if this played a role in that M5 crash in that other topic. Has anyone had "soft brakes" or brake system/stability/tyre monitor failures?

Replied to u before on this. I think your brake pump is gone. I have heard of F10 M5 having this issue locally and they replaced the pump. Get it done asap before anything nasty happens!

[singularity]

Faulty brake pedal sensor, which caused problems when turning ignition and making my pedal "extremely soft", and during inspection failed completely at BMW service was replaced today.

As for my brakes going extremely soft (80% less brake power) they said "it's probably because of too frequent brake application... brake fluids got heated up... oxygen bubbles in the fluid rose above... (I stopped listening at this stage). The real reason was probably the faulty sensor. Future will tell.

[singularity]

Or could it be that stock brake fluid can't take 5 minutes of street racing?

[Merc1]

What nonsense. A BMW M5 can't take frequent brake applications? Service guy is fulla shyte and/or just doesn't know what he is talking about. It was the sensor, if not then there a serious flaw in the design...which I seriously doubt as much as these cars have been flogged around by the press.


M

[singularity]

I just did another 3 minute, very aggressive driving with a Maserati. Frequent hard brake applications and one high-speed brake application to a full stop - brakes went soft. Not very soft, but definitely and noticeably soft. They became about 50% softer than when usual. After about 6-7 minutes of normal driving they went back to normal.

Is it normal that a car's brakes goes soft in 3 minutes of heavy short and full stop brake applications? Other than being "very different", does this softness actually affect brake distance if I continued driving like that?

[clar]

Originally Posted by singularity

I just did another 3 minute, very aggressive driving with a Maserati. Frequent hard brake applications and one high-speed brake application to a full stop - brakes went soft. Not very soft, but definitely and noticeably soft. They became about 50% softer than when usual. After about 6-7 minutes of normal driving they went back to normal.

Is it normal that a car's brakes goes soft in 3 minutes of heavy short and full stop brake applications? Other than being "very different", does this softness actually affect brake distance if I continued driving like that?

Dude, sounds like u need the carbon ceramics.