Your brakes are essential to the safe operation of your car, so why would you ignore your failing BMW 540i brake pads? Chances are you probably wouldn't, but you may not be aware of the signs of excessive wear to your 540i brake pads. First, you should be familiar with the composition of your BMW 540i brake pads. Your 540i brake pads are made with a thick frictional lining that is mounted on a metal backing plate with either rivets or glue.

This frictional lining is brought into contact with your brake rotors whenever you engage your brakes. Since the lining is softer than the solid metal rotors, it stands to reason that your BMW 540i brake pads are going to wear down over time.

The rate of erosion for your 540i brake pads will depend on the type of material the lining is made with as well as the way you drive. If you have metallic BMW 540i brake pads, they are typically made with powdered copper or bronze along with some friction-boosting fillers.

It is likely that you have soft 540i brake pads, which are made with high-temperature resin and organic fillers. Soft BMW 540i brake pads must be changed more often than metallic types, but the upside to using them is that they do not damage the rotors as metallic 540i brake pads do. There are two ways to determine when your BMW 540i brake pads need to be changed. The first is visually: you should be able to see your 540i brake pads from outside the front tires, through the openings on the wheel-rim assembly. If the lining thickness of your BMW 540i brake pads is less than a quarter of an inch, you will need to change them as soon as possible. Another sign that you need new 540i brake pads is a squealing noise that sounds as your drive and stops when you engage your brakes.