All about modern BMW Brake Service By Mporium BMW, LLC

As the “Ultimate Driving Machine”, your BMW’s braking components are an integral part of a larger system designed to provide stability and adequate stopping performance to match its forward moving performance. This is certainly understood for enthusiast minded owners of the highest performance ///M models, but for many others, brakes can be taken for granted and simply considered a nuisance to their pocketbook when it comes time to service their components. In this article, we will discuss a variety of considerations when it finally comes time for their service.

How do I know when my brake system needs service?

In most modern BMW’s even those dating back to the 1980’s, BMW brake systems employ a “pad wear” sensor which is installed as part of the brake pad. As a new brake pad (usually 10mm thick) wears down over time, it becomes thinner. As the pad becomes thinner it grinds down the sacrificial pad wear sensor against the rotor until the sensor circuit opens and tells the body computer, storing a fault. This is engineered to occur when brake pad material is worn to a thickness of approximately 3-4mm. A visual notification such as “Brake Pads Due” now occurs prompting the driver to schedule service. Older models have a service light in the instrument cluster, but modern systems prompt the driver via the Service Menu, which can be viewed under Vehicle Information and Service Info in the iDrive system. Some models calculate an estimated mileage remaining before service might be due. Once a wear fault is stored, the vehicle reminds the driver every time it is driven. It can be a nuisance to many drivers, so prompt attention to the maintenance is often desired.

How often do BMW brakes require service?

A vehicle’s brakes are split up into two systems, Front and Rear. One or the other are typically due at separate times, however we find that some X-Drive vehicles like certain X3 and X4 may wear evenly and become due at roughly the same time.

For ///M models that see extensive high performance driving or track use, brake service can be expected quite frequently, as often as every few track days. Typically, OE brakes on these cars may last 30,000 miles or more before needing service when seeing street duty. Non-performance models like a highway driven 320i can see brake pad and rotor life exceeding 60,000 miles or so before needing replacement. We usually find that most models land somewhere between these extremes. Therefore, brake service is quite infrequent and is a rare expense. When performed properly and thoroughly, its cost can be averaged out over many years. If shortcuts are taken however, costs in the long run will increase, and can result in poor performance and reduced safety.

How should BMW brakes be properly serviced?

A complete and thorough brake job for most BMW’s includes renewing the Pads, Rotors, Pad wear sensor, and servicing and/or lubricating brake caliper components during reassembly. This is universally true however some who are unfamiliar with modern euro brake technology might consider the rotors as optional which we’ll clarify next.

Rotors (aka Discs) are the heat-sink for the system and these discs receive significant wear which heats them up to very high temperatures and wears down their thickness over time, even changing their metallurgical properties in some instances. It’s perhaps an oversimplification to state that the two primary factors for assessing rotors for reuse are wear surface thickness and condition. BMW specifies a “Minimum Thickness” for the rotors which is designated as the minimum thickness allowable to perform as designed. This is measured precisely to an accuracy 1/100 of a millimeter. As pads wear to their rotors over time they create matching peaks and valleys, grooving, gouges, etc, thus causing pads and rotors to be mated to each other. To install new pads against this worn disc surface would result in less than 100% pad-to-rotor contact and improper wear of the new pads, resulting in problems like shortened service life, noise, and poor stopping. For this reason, the disc must be either replaced or resurfaced. Whether the disc can be resurfaced depends on the disc type, and thickness that will remain after refinishing them on a brake lathe. If they will be too thin they must be replaced as they will be subject to overheating, warping, etc. Furthermore, some rotor types are not recommended for machining, such as floating rotors or some drilled rotors.

How much should a BMW brake service cost?

Truly, brake system services consist of more than simply bolting in new pads and rotors. The final job quality is only as good as the person performing the work. Evaluating the type of components equipped and assessing their function and condition is critical. Making sure parts that are supposed to slide, slide. Identifying and installing the correct types of lubricant in the prescribed locations, backer adhesives in the proper place when needed, pad shimming where appropriate, etc. Ensuring brake system integrity requires knowledge and expertise that isn’t universal in every person attempting brake work across various facilities.

After a brake service is completed, the vehicle must be driven purposefully to “bed-in” the new friction components. This is an often overlooked procedure but consumes a technician’s time and affects the final product, critical towards ensuring long life and quiet function.

Of course, a base model 328i brake service cost will be significantly different than a performance model with carbon ceramic brakes like the M3 pictured above. Still, there are variations of 328 brake systems that require scrutiny when quoting. For example, a 328i might be equipped with M-sport brake package which might add hundreds of dollars to the quote over a base brake system. Some original sale regions may dictate different brake components for some models. For these reasons, it is common for reputable shops to avoid quoting brake services over the phone and setting false expectations. “Big Box” shops may quote a low labor price to get you in the door only to correct their parts pricing on inspection or inform the customer that special order parts will cause delays. This leads to customer frustrations that can be avoided.

Often, owners desiring lower up-front costs for a brake service often create a self-inflicted situation of “false economy”. Most commonly (especially in the DIY realm), rotors are reused and only pads are replaced which usually leads to shorter lifespan of pads, reduced braking performance, noisy brakes, vibrations under braking, or premature failure of the new pads due to uneven wear. Any of these situations will mandate repeating the brake service again, well before the next expected interval of 30k+ miles. Doing the job correctly and thoroughly the first time guarantees the system will function as designed for the longest possible service life. Wisdom of “Pay once, cry once” applies here.

A basic estimate may be available after providing a VIN number, however it cannot account for any possible lathe-cutting of the rotors, if any parts have been retrofitted or altered, or if the system suffers from severe corrosion, faulty prior repairs, seized hardware etc. All phone or email quotes by Mporium assume the complete Pads/Rotors/Sensor/Labor job scope and assumes there are no complications. Once an appointment is made and the brake system inspected for any other defects, an accurate estimate is provided for approval.

Why do shops usually quote new rotors?

In an effort to constantly improve performance against their competition, reduce unsprung weight etc, many BMW models have designed rotors just thick enough to wear to their minimum specifications through a single lifecycle of pads. Fewer and fewer models now have enough “meat on the bone” to allow repeated cutting. Lathe resurfacing these rotors for a second pad lifecycle will almost certainly result in rotors worn well past their safe minimums by the time the second set of pads is worn down. There are occasional exceptions however and do require a technician inspect the brake parts to determine if cutting is recommended or even possible.

We also recommend new rotors to renew their condition as the worn iron rotors are almost always rusted and certainly unsightly after a few years in use. On some examples, we find the internal cooling vanes are so rusted that their internal structure is blocking airflow or coming apart! New rotors feature fresh anti-rust coatings, and new castings will be void of any structural deformities such as warpage, uneven pad deposits, or even Cementite, which is another metallurgical defect outside the scope of this article.

Especially when diagnosing concerns such as vibrations while braking, installing new rotors is the truly fail-safe method to ensure as-new performance, cosmetics, and renewed life expectancy. It is also the only method that ensures the whole brake job receives our 2yr/24k miles shop warranty.

OEM parts or Aftermarket brands?

Another factor directly related to cost are the components and is another potential contributor to false economy. Not all brake parts are created equal! OEM parts must be used as the baseline when assessing costs as they are directly related to how long the final job will last, not just linked to performance. There is no shortage of sub-par brake parts being sold at a fraction of OEM cost, and installation of these parts should be avoided. Some shops quoting suspiciously low prices are almost certainly installing non-OE grade parts. Even worse, some facilities invoice customers at OEM price, but install low grade parts to maximize profits. A top shop always quotes OEM parts and will never allow substitution of low-quality parts in order to cut job prices.

Who should service my BMW’s brakes?

Brake service is a very common service request for almost any repair facility. As such, an owner will face many options and expect a wide range of quotes. There are no shortages of shops willing to state a lower price to get you in the door, but an educated customer can use these tips to help identify who should be working on their BMW. We recommend assessing the shop’s reputation first, and consider their estimate only after you’ve evaluated the shop according to the topics noted above in this article. A top-tier independent like Mporium understands modern systems thoroughly, with an exhaustive knowledge base not diluted across numerous vehicle brands.

Being made aware of the potential “gotchas” in this area helps you be better informed about what is involved in BMW brake service in the north Dallas and McKinney area. Choose a shop like Mporium that prioritizes quality of work and attention to detail. Even for the DIY enthusiast, awareness of these caveats can help in the decision-making process as to whether it should be attempted or left to a skilled professional.

Mporium offers OEM brake parts as well as upgraded and performance options at competitive prices. As we service BMW and MINI exclusively, we carry an extensive inventory on-site that covers almost every application for fast turn-around, usually only a few hours. We can advise each customer after a consultation, often recommending alternative items such as ceramic pad options to reduce brake dust and keep your wheels clean longer.

If your BMW or MINI is telling you that its brakes are due, let Mporium discuss options with you. Our skilled staff will help ensure that your freshly renewed brake system will be optimized for many more years of carefree service.