S4_Cinci (I S'edTFA)

In my case, I just changed out my front pads as the outer pads were worn to less than 1 mm (at least one of them was this thin) and to my surprise, the pad with the most material left was the inner pad with the wear sensor in it on both wheels (I'm stock with the HP2 calipers and OEM factory pads). The outer pads were chipping away at the edges, while the inner ones looked pretty evenly worn, but had at least 3-4 mm more material left than the outer pads.

Dealer refused to change them under warranty (no big deal there), but if I had not paid attention, I would have been stopping with the metal backing plate and the wear light would not have come on yet.

You have been warned. BTW - I put on the EBC GreenStuff pads, but they are not yet fully bedded in, so no real review possible, but they do have some decent bite right now. Will update in a few days after wearing them in...

The S

The caliper may be hanging up for only one side to wear, check it out.

ETA 4 SEC

ygm

WindyCityS4

If got new pads in, then the caliper at least floats. Odds on him lubricating the floater pins?

S4_Cinci (I S'edTFA)

Used high temp, synthetic grease as well. No cheap crap for me. I've been doing brakes for a while now, but usually on floating caliper Detroit/Japanese iron.

First thing I checked were the floating pins. It wasn't from sticking. My guess is that due to me washing my car excessively (well, in my wife's opinion), the outside pads get much more exposure to water and possibly the oxide buildup on the rotors contributed to the pads flaking at the edges and this accelerated the wear on the outer pads. ONly a theory, but otherwise no evidence to explain this uneven wear.

If you have any ideas, I'd welcome them.

WindyCityS4

the splash shield retaining extra heat and causing elevated wear. As for the outer wearing fasters, look at what could cause it....

extra pressure
extra heat
extra friction
an odd fluke.

The pressure...I doubt it on a floating caliper
The extra heat....maybe, but unlikely
The extra friction from the outer rotor seeing more corrision.....The rotor is usually swept clean in the first brake application, so it might be, but again unlikely.

I can't think of any controllable factor that would cause it. By all means, don't wash the car less! 8-)

The long term savings of a well maintained car will offset the 10% increased pad change frequency. If that is even the cause.

S4_Cinci (I S'edTFA)

Is it still considered a floating caliper design? And what is the difference between the HP2's and the OEM rear brake design. Are they both floating caliper, but the fronts are fixed pads while the rears are floating pads? I am more used to the typical stock type with single piston and two pins, with the caliper floating on a fixed saddle. I always lube the hell out of the pins ever since a brake shop tried to screw me a while back telling me I needed new calipers due to uneven pad wear when in reality a little lube on the pins did the trick (and also with single pistons and large pads, one always seemed to wear faster than the other, but usually it was the pad against the piston, not the outside pad).

S4_Cinci (I S'edTFA)

Back at you!

WindyCityS4

The designs are different front to back.
The fronts are a 2 piece design with the outer half bolted to the inner half. The caliper and carrier act like a single unit. Just a guess from here on....This most likely made the machining work easier for the piston cylinders and fluid paths. The ablilty to get more detailed on each half, the pads are able to be carried in each caliper half.

On the rear, the entire caliper is a single piece and the carrier is a different piece. The rear is a much simpler/more convential design.

S4_Cinci (I S'edTFA)

the pads, then realized they were not fixed. Still, the simplest pad change ever, IMO. I had done the rears before (on my B5 Passat).