18 X5d High pitched squeal when depressing brake pedal (car stationary)

[18X5dEd]

When I depress the brake pedal I hear a high pitched squeal for about 2-3 seconds. This has been occurring 1st start of the day and after leaving the car during the day for 30 minutes and continuing my journey.
Does this indicate that there is a leak in the braking system?
Or that the brakes were bled improperly?
Thanks for your input!

2018 F15 X5 35d 18,500 miles (less than 60 days post Manufacturers warranty)

[Clifton]

To help understand the steps to replicate,

1. Car is stationary
2. Foot on brake
3. Depress start/stop button (engine comes to life)
4. Brakes squeal??

While in Park, does the squeal immediately stop when foot is removed from brake and return if pressure is applied?

[18X5dEd]

Originally Posted by Clifton

To help understand the steps to replicate,

1. Car is stationary
2. Foot on brake
3. Depress start/stop button (engine comes to life)
4. Brakes squeal??

While in Park, does the squeal immediately stop when foot is removed from brake and return if pressure is applied?

Thank you, Clifton,
Stationary ..........in park........engine off
When depressing the brake pedal.......prior to pressing the start/stop button,
a high pitched sound is heard upon depressing the pedal in preparation to press start. Continue to hold pressure on the brake pedal.......noise stops after 2-3 seconds. The noise stops with pressure applied and does not return unless the vehicle has remained unused for 30min to 1 hr.
It has the sound of something 'venting' like a pressured gas through a small aperture.

Is that a better description?
Thank you!

[Clifton]

That helps - Is the car new to you? Unless you are describing something else, I think what you are hearing is normal. Prior to starting, my X5d makes several "activation" noises, one of which is high pitched. Pretty sure what you are hearing is one of the systems initializing.

Your brake system is not leaking, I fairly certain. Loss of brake fluid would cause the the pedal to go to the floor and the dash would light up with a low fluid warning. There would also be puddles of brake fluid as well.

Unless you are seeing warnings on the dash, or if you have a code reader to pull any faults, I think you are ok.

[///d]

You could be hearing vacuum hose noise since the engine is not running and everything is "cold".

If you leave the engine off and pump the brakes a few times do they stiffen up and remain stiff until you start the engine? They should remain stiff for quite some time if you never start the engine to create vacuum, sometimes they will remain stiff indefinitely until you start the engine. If they soften up right away you might have a vacuum leak starting, and you're hearing air escape.

[18X5dEd]

Originally Posted by Clifton

That helps - Is the car new to you? Unless you are describing something else, I think what you are hearing is normal. Prior to starting, my X5d makes several "activation" noises, one of which is high pitched. Pretty sure what you are hearing is one of the systems initializing.

Your brake system is not leaking, I fairly certain. Loss of brake fluid would cause the the pedal to go to the floor and the dash would light up with a low fluid warning. There would also be puddles of brake fluid as well.

Unless you are seeing warnings on the dash, or if you have a code reader to pull any faults, I think you are ok.

I have owned my '18 X5d since new with 4 mi on the ODO. No fluid leaks or warning lights. Thanks for the feedback! The sound could be a vacuum leak beginning as another helpful member has suggested.

[18X5dEd]

Originally Posted by ///d

You could be hearing vacuum hose noise since the engine is not running and everything is "cold".

If you leave the engine off and pump the brakes a few times do they stiffen up and remain stiff until you start the engine? They should remain stiff for quite some time if you never start the engine to create vacuum, sometimes they will remain stiff indefinitely until you start the engine. If they soften up right away you might have a vacuum leak starting, and you're hearing air escape.

Yes pump and stiffen, all the time. Have noticed this in many cars that I have owned and it applies to this X5d. What would be the implications on the braking system with vacuum failure? Loss of power assist? This symptom has started in the last month.
In April, I had the fuel pump failure and replacement of the entire fuel system from the gas tank to the injectors. Could this recent noise be related to this event?

Thanks

[Monkeypoop]

I had the same issue and it turned out to be a faulty mater cylinder on my 2017…. It squealed on start and felt not firm, but not mushy. Did a brake fluid change and the pedal went to the floor to brake. Replaced master cylinder and no issues since.

[sukhk527]

Experiencing this currently on my 17. I guess I'll look into replacing the master cylinder.

[Monkeypoop]

Originally Posted by sukhk527

Experiencing this currently on my 17. I guess I'll look into replacing the master cylinder.

Replaced with: TRW-PMH587