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Rear Brakes

    During my quest to rid the M Roadster of rattles and squeaks it became obvious that the rear brake pad “anti-rattle” clips and any sound control compound or coating that had been applied to the back of the pads was not doing the job. I’m also not a big fan of “drilled for aesthetics” rotors, so it was time for a complete rebuild and refresh of the rear anchors.

    It started like this:

    The parking brake shoes had seen better days; the parking brake had either been left engaged or had been poorly adjusted for a period of time, so time for new shoes:

    Old vs. New Parking Brake Shoes

    All the crusty old bits stripped off:

    The caliper bores and pistons looked great, no corrosion or unusual wear; a new set of seals and I was good to go:

    Z3 M Roadster Rear Caliper Pads, Piston, Seals, and Hardware

    Although I could have cleaned up the old caliper guide pins, new hardware seemed like a good idea. BMW specifically recommends against applying lubricant to the pins, but at some point caliper grease had been smeared onto the old pins, which turned into sticky goo.

    I considered going with stainless steel HEL motorcycle bleed screws, but with a little bit of thread seal / locker painted on the threads these aftermarket Carlson bleeders will be fine for my fair weather ride:

    M7 X 1.0 X 32 Caliper Bleeder Screws

    Beware, the small dowel pin, shown in the upper left corner of the parking brake hardware photo below can easily go missing. The pin fastens the parking brake cable to the actuating arm directing below it in the photo:

    Z3 M Roadster Parking Brake Hardware

    I went with StopTech braided stainless steel jacketed brake hoses:

    Stoptech and OEM rear brake hoses:

    While I’m happy with the Stoptech hoses, they are not keyed for the chassis mounting brackets like the OEM hoses, and a washer is used to compensate.  It’s my understanding the Centric and StopTech stainless braided brake hoses are the same parts, and use the same numbering system; StopTech is the Centric Parts high performance and racing brand.

    StopTech SS vs. OE Rear Brake Hose End
    Z3 M Roadster Rear Brake Hose Mount

    I went with Centric OE quality high carbon steel rotors. To avoid any pad break-in issues, I strongly suggest removing the anti-rust coating from the machined surfaces; scrub the pad contact area using an appropriate de-greasing solvent such as lacquer thinner or aerosol brake cleaner, then another scrub in hot soapy water:

    Rotor Bath
    New Parking Brake Shoes Installed

    After thoroughly cleaning the caliper castings I used VHT High Heat (550°F) “Cast Iron” finish engine paint to make the calipers pretty; the paint is holding up well a year later.   There is only one rear brake wear sensor, located on the right side.  Wear sensors can be reused if they haven’t been triggered by pad wear, but sensors are inexpensive, so I replaced the original sensor with a new one.

    I flushed the brake system and refilled it with ATE SL.6 DOT 4 brake fluid:

    The annoying brake pad rattle is gone and no more crusty calipers or boy racer drilled rotors peeking through the Roadstars:

    I used BMW, Centric / StopTech, and ATE parts for the rear brake rebuild, and have been pleased in most cases; I was not happy with the Centric low dust ceramic pads that I initially installed.

    The Centric pads stopped great and the wheels stayed clean, unfortunately the pads were noisy, but oddly just when moving in reverse. The Centric ceramic pads would often emit an annoying squeak / squeal when tapping the brakes while backing up, but were generally quiet during most driving conditions.

    I switched to OEM flavor Texstar pads and no more noise issues, just a bit more brake dust; given a choice, I’ll take dirty wheels over noisy brakes.