Advice on brake pads

  • 2003 BMW 325I
  • 60,000 MILES
Should I buy authorized BMW disc brake pads for $124 both front pads - vs. Good quality porcelain brake pads from "Auto Zone" $58 both front pads? ("Auto Zone" also sells cheaper pads into the $24.00 range)
Authorized BMW Parts Dept do not sell porcelain brakes, BMW Parts Dept. Tells me that porcelain brakes are too hard of a surface and decrees stopping power. They also say that porcelain will squeak. I'm not too concerned about the price, but do porcelain breaks decrees stopping power. I like the idea of porcelain also because I hear that there is no black brake dust left on your rims that needs to be washed off all the time at the car wash. Is this just a sales pitch to buy genuine BMW parts for twice as much money at the dealership? Or is it unwise to buy anything else besides authorize BMW brake pads that believe that damn black dust on my rims?
Do you
have the same problem?
Tuesday, April 30th, 2013 AT 11:20 PM

1 Reply

The black dust is a byproduct of higher-quality linings. The lowest-quality, but effective, asbestos linings didn't squeal or make dust that stuck to wheels. Ceramic linings are not hard like a rock, like you would think of a ceramic dinner plate. All modern linings squeal due to metal chips embedded in them for heat dissipation. Some of them tend to squeal more in humid conditions, and many of them squeal until they warm up. A lot of the squeal also has to do with how the pads are prepared by the mechanic just before he installs them. Do-it-yourselfers can expect squeals and other noises and vibrations if they don't do the same things mechanics do and don't do.

As for stopping power, the dealer is wrong. All manufacturers of cars go through a real lot of research and development to design a brake system that is specifically balanced front-to-rear to each car. They take into account optional equipment like air conditioning and power windows that adds weight more to the front or rear of the car. The proportioning valve for the rear brakes is tailored to the particular car to provide maximum rear brake power while reducing the tendency for them to lock up under hard braking. Part of the design includes the square inches of lining at each wheel and most importantly, the "coefficient of friction". That has to do with how much they stick to the rotor under a certain pressure, and how that changes at different temperatures.

Aftermarket brake parts suppliers are free to manufacture replacement parts out of any material they want to offer but they have to maintain the same coefficient of friction under all possible conditions, so to say you have to stick with BMW parts is not true. Sometimes you will find replacement linings are longer or shorter than the originals. That is to maintain the same stopping power when the friction is different. If a manufacturer did not adhere to the design specs and their pads had less stopping power, you would have to push harder on the brake pedal to slow down, and that could lead to rear-wheel lockup. That is a serious condition because skidding tires have no traction and it is common for the rear wheels to want pass the front ones. Avoiding that is the reason rear-wheel anti-lock brakes were developed for pickup trucks. You can be sure a design defect like that would result in huge lawsuits against the brake parts manufacturer, and it would extend to any auto parts store that sold them and any mechanic and shop that installed them.

BMW is well-known as the only manufacturer in the world that will not share any of their repair information. They don't want you going to any independent repair shop, just to their dealers. They won't even release their paint codes to the automotive paint manufacturers. That alone is enough reason that many of us would never own a BMW. They do not have the customers' best interest at heart.

I have always used the cheapest pads I could find and have never had a problem because of those strict design requirements. In fact, as a brake system specialist at a very nice Chrysler dealership, they stocked pads for all of their models that cost less retail than what you would pay at an auto parts store. The salesman stopped in once a week to check our inventory and see what we needed. Those linings never squealed or caused any other problems. I probably performed over 400 brake jobs in the ten years I was there. That is proof more expensive is not necessarily better. Money may be no object to you, and that's wonderful, but most mechanics don't look at it that way. We are just as concerned about our customers' wallets as they are, but we have to be careful to not cut too many corners that it comes back to bite us in the form of a new problem we caused. We wouldn't have used those cheap brake pads if we thought there was a possibility of that happening.

The front linings on my daily driver rusty trusty '88 Grand Caravan are those same cheap linings that are over eight years old and have 48,000 miles on them. If I saw them on your car I would think you just put them on because they look as thick as when they were new. BMW is very proud of their parts as shown by the ridiculous prices they charge. In my opinion you are not getting your money's worth and you are not getting better parts just because they cost more. I can't speak specifically to BMW but most car manufacturers buy their brake pads and shoes from other suppliers. They don't make their own. Why should they when they have access to companies that specialize in that? Those suppliers sell the same parts to the Auto Zones and Napas, so in theory you could end up with a set of brake pads that came off the same manufacturing line as those that were shipped to BMW.

Finally, the name on the part has no affect on the cost of gluing the lining to the backing plate so a BMW part should cost the same as my Dodge pads. The differences come in when they need to add silencers or anti-rattle springs and clips to solve a design problem or a minor annoyance. Riveting on a wear indicator, and other things like that adds labor cost which, when multiplied each time the part changes hands increases the cost of the part. I would be quite grumpy if I had to spend 58 bucks for a set of pads. $24.00 is more my style, but it's still more than I'm used to paying.
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Wednesday, May 1st, 2013 AT 12:27 AM

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