Brakes have failed😟 FIXED!!

[Clavurion]

How much was the brake pressure with diagnostics when pressing the brake pedal? Should go above 80 bar with max pedal force.

[X5only]

Originally Posted by Clavurion

How much was the brake pressure with diagnostics when pressing the brake pedal? Should go above 80 bar with max pedal force.

Thank you Clavurion Is this pressure value with engine running or off? Brake pedal is solid stiff with engine off. As soon as I turn the engine on, the pedal falls right to the floor.

[X5only]

Originally Posted by Clavurion

How much was the brake pressure with diagnostics when pressing the brake pedal? Should go above 80 bar with max pedal force.

Pressure at max force:
Engine off - 31 bar
Engine running- 29 bar

[X5only]

From ECSTunning:

$274.49
OEM (TRW) BMW Power Brake Booster - 34336760461

Has your brake pedal become stiff and hard to depress, or goes right to the floor with no pressure or feel, most likely the brake booster unit has failed.
Power Brake Booster Failure Symptoms
Hard pedal with no braking power
Longer stopping distance
Engine stalls with brakes applied
Brake pedal position higher than normal

$200
OEM (TRW) BMW Brake Master Cylinder - 34316757743
Brake Master Cylinder Failure Symptoms
Spongy Pedal Feel
Loss of brake operation
Poor brake performance
Internal fluid leaks
External fluid leaks

I found a great DIY for installing both MC and booster, but I hate brake bleeding, especially when dealing with air in the braking system. Might just take this work to a shop if cost is reasonable. Or maybe do all the parts install myself and have the vehicle towed to a shop just for brake bleeding.

https://xoutpost.com/bmw-sav-forums/...inder-diy.html

[Clavurion]

Originally Posted by X5only

Pressure at max force:
Engine off - 31 bar
Engine running- 29 bar

Then it sounds like failed master cylinder if you are certain there are no other leaks in the system.

[X5only]

Originally Posted by Clavurion

Then it sounds like failed master cylinder if you are certain there are no other leaks in the system.

Thank you. It looks like there're no external leaks. The brake fluid has been at max level consistently.