Brakes

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:

Stripped:

Z3 M Roadster Front Brakes Disassembled

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 H9411 M7 X 1.0 X 32mm (they're actually 30mm long) 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 (34116758107) 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.

Z3 M Roadster OEM vs. Aftermarket Front Caliper Bleed Screws

Z3 M Roadster OEM 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:

Left Front Brake Rotor

Left Front Brake Rotor

 
Right Front Brake Rotor

Right Front Brake Rotor

 
Genuine BMW Front Brake Pads

Genuine BMW Front Brake Pads

 
ATE  Caliper Pin Bushing Kit

ATE  Caliper Pin Bushing Kit

 
ATE Caliper Guide Pins

ATE Caliper Guide Pins

 
ATE Front Caliper Seal Kit

ATE Front Caliper Seal Kit

 
Front Caliper Bleed Valve

Front Caliper Bleed Valve

 
Bleed Valve Dust Cap

Bleed Valve Dust Cap

 
VHT High Heat Cast Iron Paint

VHT High Heat Cast Iron Paint

 
StopTech Front Brake Hoses

StopTech Front Brake Hoses

 
Front Caliper Anti-rattle Clip

Front Caliper Anti-rattle Clip

 
Front Brake Pad Wear Sensor

Front Brake Pad Wear Sensor

 
ATE SL.6 DOT 4 Brake Fluid

ATE SL.6 DOT 4 Brake Fluid

 
Motive Products Power Bleeder

Motive Products Power Bleeder

Z3 M Front Caliper Piston

Z3 M Front Caliper Piston

Ready for assembly:

Front Brake Rebuild - Ready for Assembly.png

Getting the pistons back into the calipers with the dust boots installed was a bit of a trick; I managed to tear one of my 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:

Front Brake Rebuild - Caliper Piston Dust Seal Installation.png

StopTech SS front brake hoses:

StopTech Front Brake Line Kit for Z3 M Roadster

StopTech Front Brake Line Kit for Z3 M Roadster

StopTech and OEM brake hose comparison:

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:

Front Brake Rebuild - OEM + StopTech Hose Ends.png

This isn't news, but the BMW plastic formulations are the absolute worst I have seen for automotive OEM parts; this brand new wire 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!

I decided not to reinstall the incredibly fragile OEM 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 cable clampage:

Front Brake Rebuild - Cable Clamp on Strut.png

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:

Z3 M Roadster Front Brake Wear Sensor

Z3 M Roadster Front Brake Wear Sensor

Left side sensor wiring and brake hose installation:

Front Brake Rebuild - Left Side Plumbing and Sensor Wiring.png

Wear sensor wire routing:

Front Brake Rebuild - Brake Wear Sensor Wire Routing.png

Anti-rattle clip installation:

Z3 M Roadster Front Caliper Anti-rattle Clip

Z3 M Roadster Front Caliper Anti-rattle Clip

Sorted:

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

Front Brake Rebuild - Pressure Bleeding.png

Done:

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

After putting a few hundred miles on the front Centric Ceramic pads I initially installed I was not happy with them; overall braking performance was fine, but I was getting annoying creaks and groans during very low speed braking. I suspected front suspension issues, but could find nothing amiss and the noise would sometimes seem to come from both front wheels, or from one side or the other depending upon the braking situation.

Since the brakes were the last thing changed, and I did not have noise issues before the front brake refresh, the Centric Ceramic pad compound was most likely the culprit.


A bit of poking around revealed that Textar is one of BMW's OEM brake pad suppliers, so I replaced the Centric Ceramics with a set of Textar front pads; problem solved, no more low speed creaking and groaning.