Why does the brake of BMW e60 become hard?
2 Answers
BMW e60 brake becoming hard is generally caused by issues with the brake booster pump or foreign objects adhering to the brake pads and calipers. Below are detailed explanations and solutions: Issues with the brake booster pump: If the car's brake suddenly becomes hard while driving, it may be due to a vacuum tube leak or blockage in the brake booster pump. In this case, you should stop the car immediately for inspection and replace the part if necessary. If the brake suddenly becomes hard after the car is turned off, it is usually because the brake booster pump stops working after the engine is off, and continuous braking depletes the vacuum force. In this situation, simply start the car to reactivate the brake booster pump. Foreign objects adhering to the brake pads and calipers: If there are foreign objects on the brake pads and calipers, the friction caused by these objects during braking can also create a sensation of the brake becoming hard. In this case, simply cleaning them will resolve the issue.
Experiencing a sudden stiff brake while driving is quite common; I've encountered this issue with my BMW E60. It's usually caused by a failure in the vacuum booster system. If the booster pump is aging, leaking air, or the pipeline is cracked, the brake loses its assist function, making the pedal extremely hard. A simple check involves opening the engine hood after parking to inspect the vacuum tube for any cracks. If this happens on the road, slow down and pull over immediately. Restarting the engine might temporarily alleviate the issue, but the underlying problem remains. Safety comes first—don't push through; head to a repair shop right away for a thorough inspection, as both the vacuum pump and booster could be the culprits. For prevention, I recommend high-mileage vehicles undergo regular oil changes and inspections of these components to avoid regrets later.
