wooster

I am currently driving a 2019 B9 S4 with 30K miles. Aggressive driving style.

The dealer service manager says he will NOT replace the worn rear pads without ALSO replacing the perfectly good rear rotors. No explanation--"It's our policy."

I have owned Audis for 20 years. I never experienced this.

SECONDLY, the dealer also says my REAR brake pads are the ones that need replacing, as they are TWICE as worn as the FRONTs. How is this possible in a car with the engine hanging out over the front axle, and with a 60/40 torque bias. The front pads should always wear out before the rears.

RickNY

If you look through this forum, you'll notice just about anyone reporting on brakes said their rear brakes went before the fronts.

Can you define "perfectly good rear rotors"? Did you check thickness, runout, etc to verify that they are "perfectly good"? Or was this just based on your visual?

The normal bias is 40/60 (front/rear) -- not sure if thats what you meant -- at any rate, keep in mind that if you dont have the sport diff with the S-sport package, the system uses the brakes to redirect torque to outer wheels when needed.

From what I found, the typical dealer ripoff pricing for a 4 wheel brake job is $1500-$2000... You'll do better going to an independent VW/Audi shop, and even better if you do it on your own -- there are a couple of very well done DIY brake threads here in the forum. One is here -- https://www.audiworld.com/forums/s4-...s4-b9-3008746/ -- there is another very good thread over at AZ - https://www.audizine.com/forum/showt...d-rotor-change

Bobby Kinstle

30K on the rear brakes on an S4? You must drive like a grandama. I've never had a set last over 25K miles. Front brakes do last longer on this model.

Also the stealership charges absurd prices for brake jobs.

A4Audi4Fun

^+1 (@RickNY) - I'm not in a position to do any car maintenance myself but I will use the AudiCare I purchased for the scheduled maintenance and maintain a service relationship for any warranty work that could be needed, but when it comes to wear and tear items like the brakes, DIY or a good independent is the way to go; that way you get to also decide if you want to replace the wear items with 3rd party offerings as well.

wooster

By "perfectly good" I am just quoting what the service manager said after he inspected the brakes.

Correct, I don't have the sport diff, so maybe that accounts for the extra rear pad wear.

Your are also right about the torque bias--I just typed it reversed.

So why do most people, as you say, report their rear brakes are more worn than the fronts? I still can't reconcile that with the balance of a car having such frontal weight distribution.

wooster

Well, maybe I just drive the S4 more in lousy winter weather so I've put on more mileage in snow and ice. Summer is for the M3.

What's your opinion on why the rear brakes go first? It just doesn't make sense to me based on simple physics of vehicle dynamics.

RickNY

If I had to guess -- the braking system is set up to apply more initial force to the rears during normal braking to reduce the amount of vehicle dipping to the front when stopping -- combined with what I said earlier regarding the torque vectoring brakes.

wooster

Certainly could be. It would reduce front end brake-dive. But that's one reason why I recently installed a KW HAS kit.

SCarGuy

The reason is very simple. Audi won't warranty the new pads unless they are also done in conjunction with new rotors.

This has been standard procedure on German cars for a very, very long time.

Many cars wear rears before fronts.....the car doesn't exactly nosedive under hard braking for a reason, despite the weight up front. Rear bias is far higher on modern cars than things in the past. Even my B7 S4 (orig owner) goes through rears faster than fronts, and it's 13 years old now

Bobby Kinstle

In the B8 S4 the brakes wore about the same but in the B9 the front brakes got bigger but the rear stayed the same. Thus the rears wear out the same as they did in the B8 and the B9 fronts last longer than the B8 fronts. (I owned both)