2015-2020 Audi RS3 Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 2015-2020 Audi RS3 (8V), the front brakes wear first and wear hardest. The fronts are a big 370 mm disc clamped by an eight-piston caliper, while the rear is a smaller 310 mm disc with a floating caliper that also carries the electronic parking brake. Plan on replacing front pads and rotors more often, inspect the rears at every front job, and never force the rear pistons back without putting the parking brake into service mode.

How the RS3 8V brake system is laid out

Audi's launch material for the 8V RS3 describes a front axle with 370 mm (14.6 in) discs and eight-piston calipers with large-area pads, with carbon-fiber ceramic front discs offered as an option. The rear axle uses 310 mm (12.2 in) discs. The ceramic option was front-only; the rear stayed steel on every car.

That split tells you most of what you need to know about wear. The front caliper has eight pistons pushing a large pad against a much larger disc, because the front axle does most of the stopping. The rear caliper is a single-piston sliding design that also houses the motor for the electro-mechanical parking brake (EPB), so the rear job is less about clamping force and more about getting the electronics right.

One detail that trips people up: the front rotor is not the same part across body styles. Rotor makers list the Sedan front disc (OE 8V0615301R / 8V0615301Q, 370 x 34 mm) as fitting the RS3 Sedan only, and not the RS3 Sportback or the TT RS. Order by body style, not just by "RS3."

Why the front brakes wear first

Every car transfers weight forward under braking, which loads the front tires and puts most of the stopping work on the front brakes. The RS3 adds to that with a 400 hp five-cylinder mounted transversely up front. A car that accelerates that hard also gets slowed from high speed that often, and the energy from each stop shows up as heat in the front discs and pads.

Audi sized the front system accordingly, but big hardware does not change the physics: front pads are consumed faster, and front rotors lose thickness and collect heat marks faster. Owners who do track days or canyon runs see this sharply, because repeated high-speed stops are exactly where front pad and rotor life disappears.

The rears are not immune. Stability control on modern cars applies individual brakes to control slides, and the quattro system's clutch sends a large share of torque to the rear axle in sporty driving, so the rear pads do real work. That is why the rear should be measured every time the fronts come off, rather than assumed fine.

Symptoms and how to tell which end needs work

• Squeal or scrape when braking gently: usually the pad wear indicator or a pad down to its backing plate. Look through the wheel at both ends; the front outer pad is easy to see behind the spokes.
• Steering wheel shake under braking from speed: this points to the front rotors, the most common cause of shake you feel in your hands. Uneven pad deposits and thickness variation are typical after hard use.
• Pulsation you feel in the seat or pedal, not the wheel: can be rear rotors. Measure both ends before buying parts.
• Brake pad warning light: the car uses an electrical wear sensor; after replacing pads at that axle, fit a new sensor rather than reusing a worn-through one.
• Parking brake fault message or grinding at the rear after a DIY job: usually the EPB was not put into service mode, or the pistons were forced back. Stop driving and have it scanned.

Always measure rotor thickness with a micrometer at several points and compare it to the minimum. On the Sedan front disc that is 32 mm from a new 34 mm, which leaves only 2 mm of usable wear. That is a small margin on a heavy, powerful car, which is one reason front rotors on the RS3 are often replaced with the pads rather than reused.

What to replace, and what to replace at the same time

Front axle

For a street-driven RS3, a front job is usually pads, rotors, a new wear sensor and a brake fluid check. Because the Sedan rotor has only 2 mm between new and minimum, reusing a rotor rarely makes sense once the pads are done. If you run track days, a two-piece floating rotor sheds heat better and cuts unsprung weight; our EBC Racing SG two-piece floating front rotors for the 2015-2020 RS3 Saloon are a direct-fit option for the Sedan. Browse more front options in our brake rotors and brake pads collections.

Rear axle

Rear pads and rotors are replaced as a pair per axle, the same as the front. The rear caliper's slide pins should be cleaned and relubricated, and the pad abutment clips replaced if they are corroded; a brake hardware kit covers those small parts. Do not reuse pads that have been contaminated with fluid or grease.

Fluid

Brake fluid absorbs moisture over time, which lowers its boiling point. For a car with this much performance, and especially one that sees track use, follow the fluid type and change interval printed on the reservoir cap and in the owner's manual.

How hard the job is on each end

Front: the fixed eight-piston caliper does not slide, so pad changes are straightforward: remove the retaining hardware, push the pistons back evenly, swap pads. Rotor replacement means removing the caliper. Torque every fastener to the value in the factory service manual and use a torque wrench on the wheel bolts.

Rear: this is where DIY jobs go wrong. The rear piston is driven by the EPB motor, so you cannot simply push or wind it back like an older mechanical caliper. Ross-Tech's EPB procedure says the parking brake must be OFF, a battery charger must be connected for the whole job because the EPB module is very sensitive to low voltage, and a scan tool must run the lining change mode (on MQB-platform cars like the 8V RS3, through the 03-ABS module) to retract the caliper before the pads come out. After the new pads and rotors are in, the same tool ends lining change mode so the motors reclamp and set clearance. Skipping these steps is how rear calipers and EPB motors get damaged.

If you do not have a scan tool that supports the VW/Audi lining change routine, have a shop do the rears. The front brakes are a reasonable driveway job for someone with basic tools and a torque wrench.

Street pads vs track pads

Many RS3 owners switch to a lower-dust ceramic street compound because the factory pads coat the wheels quickly. Others with track days move to a higher-temperature compound. Keep the rear compound matched in character to the front so the car's brake balance stays predictable, and bed in any new pad set as the pad maker instructs. See our ceramic brake pads for low-dust street options.

Frequently Asked Questions

Do the front or rear brakes wear out first on an Audi RS3?

The fronts. They carry most of the braking load thanks to forward weight transfer and a heavy engine up front, which is why Audi fitted 370 mm discs and eight-piston calipers there. Still measure the rears every time, because stability control and rear-biased torque in hard driving make the rears work too.

Do I need a scan tool to change RS3 rear brake pads?

Yes. The rear calipers have an electronic parking brake motor. A scan tool must put the system into lining change (service) mode to retract the pistons, then end that mode afterward. Forcing the pistons back can damage the caliper.

Will RS3 Sedan front rotors fit an RS3 Sportback?

Not necessarily. Rotor makers list the 370 x 34 mm Sedan front disc as fitting the Sedan only and not the Sportback or TT RS. Order by body style.

Should I replace rotors every time I replace RS3 front pads?

Usually. The Sedan front rotor goes from 34 mm new to a 32 mm minimum, so there is little material to spare. If a rotor is near minimum, heat-checked, or causes shake, replace it with the pads.

Can I put carbon ceramic brakes on the rear?

Audi only offered carbon ceramic discs at the front of the RS3. The rear stayed steel on all cars.

Sources

1. Audi RS3 Sedan 2018MY press information (Caricos) - 370 mm front discs with eight-piston calipers, carbon ceramic front option, 310 mm rear discs, 400 hp, torque sent rearward in sporty driving
2. Paragon - RS3 8V Sedan front 2-piece rotors - 370 x 34 mm, 32 mm minimum, OE numbers, Sedan-only fitment
3. Alcon Kits - RS3 8V Sedan front floating rotors - confirms front rotor dimensions, minimum thickness and fitment note
4. ForzaCCB - RS3 8V and 8Y brake fitment - rear single-piston sliding caliper with EPB, carbon ceramic front only
5. Ross-Tech Wiki - Working on the Electro-Mechanical Parking Brake - lining change mode, battery charger requirement, parking brake off, MQB uses 03-ABS