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Front Brakes

    Unlike the rear brakes, the front brakes were not annoying me with any noise or pad rattle issues, but the crusty calipers needed a refresh and the drilled rotors had to go buh-bye:

    And so it begins.  The front brake pads look relatively new, but are of an unknown manufacture; I suspect the caliper innards are all original:

    As was the case with the rear brakes, I found that the front caliper guide pins had been treated with caliper grease at some point, which had changed from a thick lubricant to adhesive glop; the BMW TIS manual ( and I think the Bentley manual too) specifically states not to lube the caliper guide pins.  Time for new pins anyway:

    New Caliper Pins vs. Old

    All the crusty old bits stripped off:

    Although I could have cleaned up the OEM bleed screws, the plating had been compromised and after removing the corrosion there would be bare steel which would have promptly started corroding again.  The aftermarket Carlson bleed screws I ended up with are proportioned a bit differently, with an 8mm hex head, compared to the OEM 7mm hex.  While the Carlson bleed screws are fine, ATE bleed screws are probably a better choice, or you could use genuine BMW front caliper bleeds screws at $10 or so each.  I’m of the opinion that it’s important to use OEM-style bleed screw rubber caps with lanyards, which serve as sensor cable ties.

    OE vs. Aftermarket Front Caliper Bleed Screws

    The front caliper pistons were not a pristine as the rears, with some minor corrosion damage on the exposed non-sealing surfaces, but still very serviceable:

    OE Front Caliper Piston

    Ready for assembly:

    Getting the pistons back into the calipers with the dust boots installed was a bit of a trick; I managed to tear one of the new dust boots before coming up with an installation technique. Lube the main seal with brake fluid and install it into the caliper.  Roll the dust boot over the piston with the lip positioned as shown below; tuck the dust boot lip into the top caliper groove, then push the piston into the caliper:

    Caliper Piston Dust Boot Installation

    StopTech braided stainless steel jacketed front brake hoses:

    StopTech Front Brake Line Kit

    StopTech and OE brake hose comparison:

    StopTech SS vs. OE Front Brake Hoses

    As was the case with the rear StopTech hoses, the hose ends are not keyed for the mounting brackets like the OEM parts; a flat washer included in the kit is needed to properly mount the hardline end of the hose to the frame bracket:

    StopTech SS vs. OE Front Brake Hoses

    While both front wheels are wired with ABS sensors, only the left side front brake assembly has a pad wear sensor; I could have reused the old one, but since everything was apart, time for a new sensor:

    This isn’t news, but the BMW plastic formulations are the absolute worst I have seen for OE automotive parts; this brand new clip that is used to tie the ABS and brake wear sensor wiring to the front strut broke while I was removing it from the frickin’ bag!

    BMW Plastic Clip Fail

    I decided not to reinstall the incredibly fragile OE sensor wire clips; during disassembly I noticed the clips on both sides were broken and had been repaired with zip ties, in addition to my experience of breaking one of the new clips while removing it from the plastic bag.  Instead I replaced the wimpy clips with 1/2″ nylon cable clamps and  10mm BMW nylock nuts:

    My improvised brake sensor cable clampage; this is the right side that only has an ABS sensor:.:

    Improvised Right Brake Sensor Cable Guide

    Left side sensor wiring and brake hose installation:

    Wear sensor wire routing:

    Caliper Anti-rattle clip installation:

    Caliper Anti-Rattle Clip

    Sorted:

    Pressure bleeding; I should have bought one of these a long time ago!

    Scwaben Pressure Bleeder

    The Schwaben pressure bleeder worked great, but the supplied brake master cylinder cap fit poorly. There’s separate blog post about the issue.

    Done: