ppinto1

I got the message in my dash today that I need to replace my pads. After a quick inspection, it seems like it's the backs.

I called the dealer for a price: $1100. I said I'd do it myself, and the service manager informed me I'd need a scan tool to set the parking brake to the service position - and told me I should replace the rotors at the same time.

I'd previously purchased the shop manual, which confirms the requirement to position the parking brake (and resulted in me ordering the VAG tool from Ross-Tech). However, the manual instructs you to inspect the rotor for runout thickness.

Has anyone only changed pads on rotors that were within tolerance? If so, what pads - and did you get warped rotors after?

I plan to order the OEM pads from genuineaudiparts.com. Does anyone disagree with this approach? I don't care about the dust as much as I want the brakes to function exactly as they do now.

Thanks in advance!

MP4.2+6.0

You don't say how many miles, which is key for an educated guess here. Yes, you have correct info, and yes you can open rear calipers with Ross-Tech VCDS, basically just like the dealer does. BTDT several pad cycles on D3 with same basic rear set up as D4. Yes, if you want OE feel to brakes, than OE pads always a good choice. Dust is more pronounced in front than rear.

On rotors, my rule of thumb is basically every other pad change, you need rotors. It can vary some by specific Audi, driving style and such. Worked well on my D3 tracking for 110K miles I have done on it, and 125K cumulative. If anything, I noticed w/ D3 it "only" went two pad cycles in back, like in the front. Older Audis seemed to wear rears pretty slowly. Air ride with D4 or D3 probably contributes to more effective braking in rear and hence more wear.

You answer it more precisely by checking the rotor thickness to be sure it is above minimum spec. Dealers like to say they want to be sure it will still be at minimum spec AFTER the whole next pad cycle if you press or notice the numbers they give you are above the min. spec, which then may lead to a prediction you will (in the future) need new rotors if they drop below spec. Thus all roads may point to selling more rotors at the dealer...funny how that works. You need to decide, but honestly within reason this is the good ole USA (for most of us here). An extreme stop or set of stops in felony territory is less than 100MPH, and for most of us most of time, 80 give or take. The system is designed and spec'ed for 155. Where that is legal in Germany it is with real world stopping or sudden slowing from 100-125 pretty commonly even if you aren't blasting down the Autobahn or doing some YouTube speed run. Remember high school physics and the square of the velocity--it's not linear as far as energy to scrub. Under spec rotors mean less mass to dissipate heat from the pad friction. Whether rotors more worn or less, the friction component though is still the same assuming same pad spec.

As a guess if, you have 35 or 40K miles, I would bet this is first pad change. If double that, second and rotors are probably due. If you are the first owner, you should know. If second owner, might be in dealer service paperwork. You should mic them anyway when you do brake work to be sure. A heads up on the tool--the simple plastic type calipers won't work because they will just measure the rotor outer wear lip. You need a tool that reaches around that; I use an old fashioned micrometer I got from my dad as a hand me down.

mbeggsRS4

I dont know how you drive, but ive noticed A8s can go a bit longer without rotors than say a A4 or a S5, due to calmer driving How many miles on the car? and do you ever notice any pulsing? Also give em a feel and see if theres a lip.



And i disagree with that approach, i say you go with Audi Parts since thats my site and we sponsor the forum

ppinto1

Thanks for the input, guys!

I have 53k miles on the car. I bought it with 42k as a CPO last December.

Is there enough room to reach a micrometer around without taking the rotor off?

If if has to come off, the shop manual says to replace the bolts that attach the caliper carrier. Do these come in the overhaul kit (3D0698671)?

To be honest, if I'm taking the rotors off to measure, I'd just as soon replace them

The brakes have never pulsed.

The Bentley manual I had for my A6's had diagnostic procedures included. For example, how to troubleshoot EVAP codes - including how to use the scan tool to set various self-tests. I didn't see that in the current manual. Did I miss something, or are they no longer included?

MbeggsRS4, I'm switching my supplier of parts. Thanks for supporting the forum!

By the way, it's been a bunch of years, but that address looks like that of a dealer where I bought my 2004 A6 2.7t CPO.

mbeggsRS4

Riverside Audi ?

ppinto1

Yes! Riverside Audi. Bad area for a test drive... But, I got a great deal

mbeggsRS4

Were no longer Riverside,they were gone before i got here. Now were Meadowlands Audi. Were a Benzel Busch Dealer.

But we are moving out of here shortly!

Are you in the area?

ppinto1

I'm live in PA, but I spend a lot of time working in DC. My A8 is from Rockville Audi.

mbeggsRS4

Not a bad ride in an A8

MP4.2+6.0

So, if you bought CPO, what does CPO paperwork say on both? See the table they fill out in Section 6.5 of the 3 page CPO checklist you got. You will have historical data here, and could extrapolate wear from it--or if swapped, will likely know from what that data says. My CPO paperwork had (almost new) wear readings, as expected at less than 4K miles. If you bought at 42K miles, I would be surprised if pads were not changed by then, since checklist says it should have at least 50% pad life. > 84K on rear pads would not be believable to me unless little old lady to church car or solely highway miles. Suggests an earlier change if you marry it with CPO history. If it weren't CPO, I could believe that a very lightly driven one might just get to your kind of miles in back. Sensors do trigger early though, so if it was at like 55% before and 30% now (like 3mm), I could see sensor now kicking in on first pad set if historically lightly driven. That is, the CPO measurement is kind of weird because I think it implies the whole pad thickness is available, while sensors kick in down around as much as 25 or 30% left. Thus, the "first half" of wear they allow, is actually the first ⅔ or more total before sensor kicks on light. All this aside, CPO paperwork will be valuable for a rotor wear reading you can just extrapolate to current miles as a guesstimate for your decision about whether to replace (order in advance) or not before any disassembly.


Yes, right below caliper as you look at it. There is a gap in there before the rotor splash/heat shield gets in way, at least on my (somewhat bigger) D4 S8 fitment. If you have open and large wheels like (5 spoker OEs for me), you could likely reach in from side of car and get at it without even a wheel pull. Rears need a 1" micrometer or similar tool, while fronts need 2".

I replace them (and suspension bolts) these days since cheap, plus per manual procedure. But what it really basically means is the new bolts have a treatment. Same basic result if you Locktite them; they aren't stretch type single use. Haven't done D4 (or similar looking Q5), but on D3 if it is just pads you just pull the caliper unit, not the carrier bracket. Look at picture below. Thus, bolt 1 that goes into floating pin 6, not bolt 10. Same as basic C5, since you and I both owned that one too--other than this one has the motorized parking brake assembly add on.

See above. Also know front rotors are pricier--the floating pin nature of them with lighter alloy hats. Rears are standard cast stuff so conventionally priced.

Not relevant if rotors did not warp or pads didn't deposit incompatible material on rotor. If you go stock to stock on pads w/ used rotors, typically no issue. If you go some ceramics on used rotors, some end up with issues.