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B5 S4 Brake Upgrade with Zimmerman Rotors - B6 Audi A4

Prior Experience: Perhaps a little
Cost: approx. depends on equipment
Time: aprrox. 5 hours

Discuss this mod - Here

You may want to paint the calipers, etc. before you install them, as it will make your life easier than painting them on the car. Against popular opinion, I decided to go with the x-drilled/slotted rotors instead of the just slotted ones. I picked them up from ECS tuning, and have been very happy with them so far.

So lets get going...

I have been meaning to get this mod written up. Its relatively easy and should only take about 5 hours. As you probably know, B6A4 brakes are pretty poor, so the B5S4 upgrade is common. These larger calipers are a direct bolt on for the a4, so it is an easy mod

B6 Audi A4 - S4 Brake Upgrade Front Replacement   B6 Audi A4 - S4 Brake Upgrade Front Replacement




SUPPLIES - Supplies are simple but prices vary. All you need are the calipers (buy used), the rotors (ECS tuning), pads - I went with pbr metal masters, and Stainless steel lines if you decide to go that route (I didn't). Also you will need to bleed the brakes, so now would be a good time to upgrade all your fluid. I flushed it and added Motul 5.1.


I learned the hard way. I was shipped 2 right front rotors, and mismatched pads!! I only found out after I had my car taken apart....DON'T MAKE THIS MISTAKE...LOOK BELOW

B6 Audi A4 - S4 Brake Upgrade Front Replacement   B6 Audi A4 - S4 Brake Upgrade Front Replacement PBR Metal Masters

After you get everything sqaured away, you can start by jacking up your car, USE JACKSTANDS, and take off the wheels. If you are changing the rotors, calipers and pads, this process is MUCH EASIER than changing individual pieces.

B6 Audi A4 - S4 Brake Upgrade Front Replacement  

You will see 2, 21mm bolts behind the calipers. These are the only bolts holding on the calipers, rotors and pads!!! You may want to get some rust-busting spray and let it sit before you start. 5 minutes waiting for the rust breaker could save you HOURS in the long run....

B6 Audi A4 - S4 Brake Upgrade Front Replacement  

Before you remove the two 21 mm bolts you should probably first disconnect the brake line. This will prevent the caliper from dangling on the line, and therefore braking/harming the line. I don remember the size of the bolts, but you just need the open end of a box wrench to disconnect it. After you unscrew it, it should slide right out of the bracket.


Now you can go ahead and remove the 2, 21 mm bolts. After these are off, there will be a few clips you need to disconnect. They are all obvious, so I wont show them here (they just hold the lines in place, and connect the brake wear sensors).

If you decide on brake pads that do not use the sensor, cut the plug off of your old pads. You can then trick the wear sensors by stripping and soldering the two wires together. You can then just plug the connector back in with the wires soldered up.

  B6 Audi A4 - S4 Brake Upgrade Front Replacement
B6 Audi A4 - S4 Brake Upgrade Front Replacement  

After you get those 2 bolts off, the entire caliper, rotors, pad and line assembly will come right off. You may need to tap it with a mallet if it is on the hub real tight, but I PROMISE there are no more bolts!


The install of the new calipers are just the reverse. After which you will have to bleed your brakes. On our vehicles, you actually have to start from the drivers front brake. If you have a manual transmission, the service procedure recommends you start with bleeding the clutch slave cylinder before proceeding to the brakes. If you are doing a complete fluid flush, you will extract the fluid from the reservoir as well. You should proceed in this order, and extract the following amounts of fluid from each spot:

100 ml
Left front
200 ml
Right front
200 ml
Left rear
200 ml
Right rear
200 ml
Total quantity
1,000 ml**

* this includes that taken from the reservoir and clutch

That is pretty much it but I will show you some other stuff here..

The b5s4 brakes require 4 pads each, so it should look like what I have below. Before you put them on the car, it will be best for you to get the pads in the calipers, and make sure the rotors fit. If the calipers are used, most of the time the pistons will not be pushed in all the way. If you need to get them in farther, you can open the bleeder valve and use a C-Clamp to get them to go...

B6 Audi A4 - S4 Brake Upgrade Front Replacement   B6 Audi A4 - S4 Brake Upgrade Front Replacement
B6 Audi A4 - S4 Brake Upgrade Front Replacement

If you decide to go with the X-drilled rotors, make sure you install them the right way. The ECS ones are usually marked, but I have seen people with them on wrong. Pictured below is my left front rotor - i.e. it would be rotating counter-clockwise while driving forward.

  B6 Audi A4 - S4 Brake Upgrade Front Replacement

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