Hard brake pedal in BMW - what is the reason and how to fix it?
What is the manifestation of hard brake pedal in BMW? In which BMW models does the phenomenon of hard brake pedal occur? What is the relationship of the vacuum pump and servomechanism to the hard brake pedal?
BMW driver question
There was a problem of hard and high brake pedal on cold engine. The impression is as if the brakes are swollen. You have to use a lot of pressure to get the car to brake. The mechanic said that it is a brake servo that is worn out and should be replaced. The car has a mileage of 62,000 km.
Is this possible with such mileage?
The problem affected a 2011 BMW F01 740D, but it happens in other models as well.
BM Cars service response
The problem you described with the so-called hard brake pedal occurs not only in older BMW models, but also in new ones after low mileage.
The cause of this phenomenon is usually a lack of brake assist caused by damage to the vacuum pump, vacuum lines or the servo itself. The location of the servo in most BMW models at the front near the bulkhead wall on the left side causes water flowing from the windshield to be trapped in the chamber if the drain lines located just near this mechanism become clogged.
Prolonged standstill of water results in corrosion of the servo, its unsealing or water getting inside and damaging the mechanism's diaphragm. To prevent this type of malfunction in the future, regularly clean the area around the water outlets from the remains of leaves and debris, especially when parking the car between trees, or in a heavily wooded area.
For a precise diagnosis, we invite you to schedule a visit to our service center.
Other BMW tips related to this topic
- Gaspedal blocking slightly
- Jerking and white smoke on cold engine in BMW 3
- Jerking and stalling of the engine in the BMW
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