2011-2019 BMW M5 Brake Noise: Squeal, Grinding and Pulsation Causes

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most brake noise on a 2011-2019 BMW M5 comes from three places: worn or unevenly worn front rotors (pulsation and judder), glazed or worn-out pads and missing anti-noise hardware (squeal), and pads worn down to metal (grinding). The M5 runs large multi-piston calipers on heavy two-piece compound rotors, so the fix is usually a matched pad and rotor job done with clean hubs, fresh shims and a proper bed-in, not just a pad slap.

This guide walks through how the M5 brake system is built, how to tell the noises apart, what causes each one, and which parts actually fix it.

How the M5 Brake System Is Built

The M5 years in this range cover two chassis generations: the F10 and the later F90. Both use what BMW calls compound brakes, meaning the rotor is not one solid iron casting. According to BMW Group's launch material for the F10 M5, the car uses six-piston caliper brakes with compound construction designed to resist fade under repeated heavy use. For the F90, BMW describes M compound brakes that are lighter than conventional grey cast iron parts, with blue six-piston fixed calipers in front, single-piston floating calipers at the rear, and perforated, internally vented discs all round. An optional M Carbon ceramic system, identified by gold calipers, was also offered on the F90.

On the F10-generation M5 (and the related F06, F12 and F13 M6), the front iron rotors measure 400 mm across and 36 mm thick when new, per Alcon's fitment data for its replacement rotor, which lists a 34 mm minimum thickness for its disc. Your own rotors carry their minimum thickness stamped on the disc; that stamped figure is the one that matters.

Two things follow from this design. First, the rotors are big and heavy, so a small amount of runout or thickness variation shows up clearly as steering wheel shake. Second, cross-drilled or perforated faces are more prone to light squeal and to pad edge wear than a plain face, especially once the pads are glazed.

Carbon ceramic cars are a different job. If your M5 has gold calipers and ceramic discs, everything below about iron rotor wear and resurfacing does not apply. Ceramic discs are inspected and replaced by different criteria, and iron-rotor parts will not fit.

Tell the Noises Apart

Ferodo's technical guide sorts brake noise by frequency, and that is a useful way to narrow down the cause before you pull a wheel.

Pulsation and Judder: Rotor Runout and Thickness Variation

A pulsing pedal or a shimmy through the wheel when slowing from highway speed is almost always a rotor issue. Ferodo lists poor fitment on the hub and excessive disc thickness variation as the main causes of low-frequency judder. Brembo gives the numbers technicians check against: brake disc runout should not exceed 0.10 mm when mounted on the car, and the wheel hub by itself should not exceed 0.050 mm.

On an M5 the common story goes like this: hard use builds heat, pad material deposits unevenly on the iron ring, and the disc develops thick and thin spots. Rust scale on the hub face does the same thing mechanically by cocking the rotor slightly, which over a few thousand miles wears the disc unevenly.

How to diagnose it:

• Note whether the shake is in the steering wheel (front rotors) or felt more through the seat and pedal (often rear).
• Measure rotor thickness in several spots around the disc with a micrometer. A consistent reading everywhere but a shaking wheel points to hub runout or mounting; varying readings point to thickness variation.
• Compare the thinnest reading to the minimum stamped on the rotor.

The fix is new rotors with new pads. Brembo advises against turning or grinding the braking surface of its discs, and on a compound rotor with a lot of heat history, replacement is the reliable answer. Before the new rotor goes on, clean the hub face down to bare metal. Browse replacement brake rotors, and for F10-generation M5 and M6 owners who track the car, the EBC Racing SG two-piece floating front rotors for the BMW M5 and M6 use floating iron rings on aluminum bells, a design meant to let the ring expand with heat without distorting.

Squeal: Pads, Shims and Caliper Hardware

Squeal is the most common complaint and the one most often misdiagnosed as bad parts. Brembo notes that squeal is frequently not caused by a defect in the new component, but by worn surrounding parts that stop the pad and disc from working together properly. The usual M5 culprits:

• Missing or reused anti-noise shims. Brembo says to install new shims correctly and not reuse old ones.
• Dirty or dry pad abutments and slides. Brembo recommends anti-noise lubricant between the caliper bracket and pads, and inspecting pistons, seals and sliding elements. Six-piston fixed calipers have no slide pins, but the pad guide surfaces and retaining springs still need to be clean and in good shape.
• Worn caliper springs. Replace weak or distorted pad retaining springs and check they sit correctly; a loose pad chatters and squeals.
• Glazed pads. Pads cooked by repeated hard stops develop a hard, shiny surface that squeals and bites poorly. New pads bedded in correctly solve it.
• Perforated rotor faces. The holes add edges for the pad to catch on. A light squeal at very low speed is more common on drilled discs.

Fresh brake pads plus a brake hardware kit with new shims and springs handles most M5 squeal complaints when the rotors are still in good condition.

Grinding: Stop and Inspect

Grinding means metal is touching metal. On an M5 that usually means the pads are worn through to the steel backing plate, or a stone or piece of rust is trapped between the pad and the disc. BMW uses electronic pad wear sensors, so a brake warning on the dash plus grinding is a strong sign the pads are finished. Continuing to drive cuts grooves into the rotor and can damage the caliper pistons.

If you hear grinding, pull the wheels and inspect all four corners. Once the backing plate has touched the rotor, plan on replacing both the pads and the rotors on that axle, and fit a new wear sensor, since the old one has done its job and is usually worn through.

What to Replace at the Same Time

Brembo's position is that when you change discs and pads, you should do a full check of the whole system, not just swap the two wear parts. On an M5 that means:

• Pads and rotors together, per axle. Brembo recommends always replacing pads when changing discs.
• Pad wear sensors on any corner where they are fitted.
• Shims, springs and retaining hardware.
• Brake fluid. Brembo recommends keeping the level between minimum and maximum and replacing the fluid every two years. Use the fluid specified in your owner's manual or on the reservoir cap.
• Hub face cleaning every time a rotor comes off.

You can find everything for the job in our brake parts catalog.

How Hard Is the Job?

A pad and rotor job on an M5 is within reach for a careful home mechanic with a good torque wrench, but it is heavier work than a typical sedan. The front rotors are large, the calipers are heavy, and the fasteners must go back to the values in the factory service manual. Plan on a few hours per axle the first time.

After installation, bedding matters. Brembo recommends a correct bed-in over about 300 km, avoiding abrupt braking during that period so the pad and disc surfaces match. Skipping this is one of the most common reasons a fresh set of M5 brakes squeals or judders within weeks.

Frequently Asked Questions

Why do my new M5 brakes squeal?

Usually because the old shims or springs were reused, the pad contact points were not cleaned and lubricated, or the pads were not bedded in. Brembo notes that new parts are rarely the cause; worn surrounding hardware usually is.

Can I resurface my M5 rotors instead of replacing them?

Brembo advises against turning or grinding the braking surface of its discs. On the M5's large compound rotors, most shops replace them, and a rotor below the minimum thickness stamped on it must be replaced.

My steering wheel shakes only when braking from high speed. Is that the rotors?

Almost always. Brembo's limits are 0.10 mm of runout for the mounted disc and 0.050 mm for the hub alone. Past that, or with uneven thickness, you feel shake. Measure thickness around the rotor and check the hub face for rust.

Do these parts fit carbon ceramic M5 brakes?

No. Cars with the optional M Carbon ceramic brakes have gold calipers and use different discs and pads. Confirm which system your car has before ordering.

Should I replace the brake wear sensor with new pads?

Yes if the sensor has been triggered or the pads wore into it. A sensor that has already warned is usually worn through and will keep the warning on.

Sources

1. BMW Group PressClub: The new BMW M5 Saloon - F10 M5 six-piston compound brakes built to resist fade
2. BMW Group PressClub: The new BMW M5 (F90) - M compound brakes, blue six-piston front and single-piston rear calipers, perforated vented discs, optional gold-caliper carbon ceramic brakes
3. Alcon: BMW M5 F10 / M6 front rotors - 400 mm x 36 mm front rotor size, 34 mm minimum for that disc, non-ceramic fitment
4. Brembo: Noises and vibrations - 0.10 mm disc and 0.050 mm hub runout limits, new shims, lubrication, two-year fluid change, 300 km bed-in
5. Ferodo: Brake noise technical tips - judder, squeal and squeak frequency ranges and causes