A Christmas Present to Myself – Audi S4 Brake Upgrade!

The brakes on my 2013 S4 are… fine. They’re fine. I mean, they have a pretty strong vibration at anything over 100 MPH as I found out on the track day, but for road use they’re… fine. What I think Audi should have put on instead are these, the 4 piston Brembo calipers from the bigger brother Audi Q5. You can actually get these on just the 2L TDI, and yet they are considerably better than the single piston sliding calipers that come on the S4 as standard. 

There are a few catches, like how the Brembo’s use a 320mm disc instead of the stock 345mm disc on the S4 – but the upside is much more even braking pressure on both pads, less vibration, an aluminium caliper for better heat dissipation, and it’s so, so much lighter. Like in the order of multiple kilos – which is great because this is unsprung weight. 

So how do you do the swap? In short, it’s pretty simple. Use a 14mm flare nut wrench to crack the brake line loose, a 21mm socket and a breaker bar to get the caliper bracket bolts loose, then in my case I just spun the caliper in my hand to remove it from the brake line. You’ll then need to switch the disk over to a slightly smaller 320mm disk instead, then you can screw the new 4 pot caliper into the brake line and bolt it up. Tighten the brake line then you can slide the new pads in, then the guide pins and anti-rattle plate, and on this side we’ll need the brake pad wear sensor connected up too.

With that done, that’s this side sorted. You’ll of course need to repeat that for the other side, then bleed the brakes. On these calipers, you’ll need to use both bleed screws on each caliper – one per side. I used the two person method with cracking the bleed screws, pushing the brake pedal, then locking the bleed screw and pumping the pedal. Sadly the inboard bleed screw on the driver’s side snapped off without budging, which meant I couldn’t bleed the air out of that caliper. 

While I did try, I actually ended up taking the calipers back off for the time being until I can extract the broken bleed screw, then I’ll stick them back on and give a full update and thoughts video!