Weird Brake Issue Coming Out Of Park - Happens Randomly

[Eljaber]

I know I have seen a thread about this in the past, I just can't find it. This has happened on my wife's 2022 ST once, but, it has happened to my 2020 ST multiple times, maybe 3-4x since owning it (June 2023). And I think I know why it happens so frequently with me because it might be the way I am doing it.

Randomly the brakes will fail to work coming out of Park and releasing the parking brake, almost as if they are only being partially applied and the vehicle will continue to move forward until you disengage the brakes and depress the brake pedal again. You can tell the issue is happening because the brake pedal has a stiffer feeling to it. The last few times it has happened, I think it's because I did everything a bit too fast and the vehicle didn't like it (I was in a rush), I depressed the brake pedal, put it into Drive, and immediately released the handbrake, the brake pedal then a weird stiff feeling, the vehicle rolls forward and if you try to apply more pressure on the brake pedal, it does not make a difference, until you get off the brake pedal and depress it again, then the brakes work properly.

I'm going to see if I can find a way to replicate it before I go for an oil change in a few weeks. either way, I will mention it to the dealer to see if they can check it. Considering it happened once on my wife's ST, I'm guessing it's another one of those weird ST glitches, only this one can have severe consequences if it happens at the wrong place and time.

 

[DaveG ST]

Trying to think why you may be using the parking brake so often. I have never used mine on my 2020 ST. I could see using it when parked on an incline or hill. Anyways, could be a brake power booster issue or brake fluid is low.

 

[bhunted1]

I have a ‘23 and first time I heard it, I’m like????
Turns out it applies the PB as soon as its put into park. I actually think its cool. Most likely air or a hydraulic sound. Sounds like a bird.
I don’t think my ‘23 gives you an option to turn it off permanently.


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[hbalek]

I have a ‘23 and first time I heard it, I’m like????
Turns out it applies the PB as soon as its put into park. I actually think its cool. Most likely air or a hydraulic sound. Sounds like a bird.
I don’t think my ‘23 gives you an option to turn it off permanently.


Sent from my iPhone using Tapatalk

All e-brakes sound like that. My 2013 MKZ made that similiar sound and my Fusion Hybrid at work also makes that sound. They are not auto-engage however neither is my 2020 ST. They added that to the models with one less subrame/rear differential bolt as part of a safety recall. I use mine all the time but use the auto release feature when I put it in drive. I LOVE the auto-hold as this is my first vehicle with that feaure. I can't live without it! As for the braking issue that the OP mentioned, I believe there's a TSB for it. It has something to do with the actuator pump or something. I use auto-start most of the time so I rarely have an issue with it, but I remember when it was new almost 4 years ago I remember having to push the pedal down really hard to get full brake power after cold start. I found these old discussions of a similar issue. It was referred to as a brake booster problem in the second topic:

https://www.explorerst.org/threads/brake-applied-power-reduced.3550/#post-45572

https://www.explorerst.org/threads/rolling-backward-holding-brake.4276/

 

[Eljaber]

All e-brakes sound like that. My 2013 MKZ made that similiar sound and my Fusion Hybrid at work also makes that sound. They are not auto-engage however neither is my 2020 ST. They added that to the models with one less subrame/rear differential bolt as part of a safety recall. I use mine all the time but use the auto release feature when I put it in drive. I LOVE the auto-hold as this is my first vehicle with that feaure. I can't live without it! As for the braking issue that the OP mentioned, I believe there's a TSB for it. It has something to do with the actuator pump or something. I use auto-start most of the time so I rarely have an issue with it, but I remember when it was new almost 4 years ago I remember having to push the pedal down really hard to get full brake power after cold start. I found these old discussions of a similar issue. I was referred to as a brake booster problem in the second topic:

https://www.explorerst.org/threads/brake-applied-power-reduced.3550/#post-45572

https://www.explorerst.org/threads/rolling-backward-holding-brake.4276/

Thanks! I will check those threads this weekend.

As for why I always use the e-brake, well, it's from habit. Our driveway has a small incline and the parking lot at work as well.

 

[bosephbarking]

Dealer is replacing my electronic brake booster. These cars use an electric pump to pressurize the system. Sounds like yours is failing. If you are still under warranty take it in immediately.