After a series of delays we're now gathering pace with our 2008 Audi TT 2.0T project build. We previously fitted an Audi Genuine Accessories body kit and 19" Turbo Twist wheels, while last month we added H&R coilovers and sway bars to the mix. This month, we're delving deeper into the Audi parts bin to carry out a TT RS brake upgrade.

What's interesting about this is that while it fitted our TT, it should equally apply to the Audi A3 and Golf GTI, which share many components, although we can't verify this since we haven't attempted the swap ourselves.

To be honest, we were unsure about exactly what parts we'd need so ordered too many pieces, but fortunately our local Audi dealer kindly took most of them back. While looking at the part numbers, the Audi catalog suggested we'd need all manner of fittings and fixings, which turned out to be misleading. While different part numbers are used, many of the parts needed were identical for both the 2.0T and RS variants.

With everybody having easy access to the Audi parts center at your local dealership, the possibility of used parts becoming available in the future, and considering these are high-quality Brembo calipers with large 14.6" (370mm) rotors, we thought a conversion using only OEM parts would be an interesting story if we could make it work.

After a series of missteps, we believe we now have a definitive list of parts and instructions on what to do. We should point out, however, this guide is advisory so please check fitment, clearance and tightening torque values to ensure your own installation is secure. Modifying your brakes can be a risky business. If you're unsure or inexperienced, consult a specialist for parts and fitting.

We should also point out that an aftermarket Brembo kit would be cheaper to buy, but this TT RS conversion is for all the OEM+ enthusiasts who like to keep it in the VAG family.

The Parts

You'll be glad to know we made all the mistakes for you, but were able to narrow down precisely what you'll need. Of course, different models may vary but assuming you have the same original equipment as our '08 TT 2.0T, this is what you should need: the left and right TT RS four-piston Brembo calipers (supplied with the carriers/adapters, pad springs and retaining pins), a set of pads, a pad sensor (not shown), two 14.6" rotors (same parts number for both sides), left and right heat shields, brake lines, left and right brackets and the caliper bolts (although we re-used all our original bolts and screws). See the table below for part numbers.

You'll also need new brake fluid to bleed the system as well as brake cleaner and grease.

The fitting was straightforward and certainly a DIY proposition if you have good tools, previous experience and know how to bleed brakes properly. You'll need to raise the car but could do it on axle stands rather than a full lift. Air tools are helpful for the carrier bolts but not essential.

Fitting

To begin, remove the front wheels and undo the two 21mm bolts securing the caliper carrier to the wheel hub. Hang the stock caliper out of the way to avoid stretching the brake line. We will disconnect the caliper last to minimize brake fluid loss.

Now undo the single T30 torx screw from the stock 12.25" (310mm) rotor (our car had Brembo Sport rotors fitted previously) so it can be removed. You can then undo the three T30 button-head screws that secure the heat shield. Finally, undo the 10mm bolt for the bracket on the suspension upright: it's used to route the brake line and ABS cable.

You can now fit the new parts, first fitting the new bracket that will secure the new rubber brake line in place. Then attach the larger heat shield with the original screws and the new 14.6" drilled TT RS rotor. The rotors are directional but Audi only provides one part number, so they don't consider it important to have the vanes rotate in any particular direction.

The new Brembo RS caliper is supplied with the carrier attached. We found our original 21mm bolts from the 2.0T carrier identical to the new part numbers used for the RS carriers, so we re-used ours but have provided the part number in case you want to incorporate new ones.

With the four-piston caliper in place, fit the brake pads. These are secured by a metal spring that is kept in place by retaining pins. Grease the pins before inserting to make the job easier.

With the brakes fitted, the most difficult task was fitting the lines and bleeding the fluid to remove air bubbles. Start by fitting the banjo joint on the rubber brake line into the caliper. The other end is connected to the hydraulic system by first undoing the line on the stock caliper where it connects at the top of the inner fender. You then screw the new rubber line into the connection, but do so quickly since it can be very messy. Fluid will spill from the line when you undo the connector. This fluid can strip paint, so wipe spills immediately with a separate cloth. The displaced fluid will be replaced with air, which you must bleed from the system to ensure a solid brake pedal.

When bleeding the brakes, we used a vacuum brake bleeder that draws fluid through the calipers to remove air in the system. We bled both front calipers and even did the rears to ensure there was new fluid throughout the system. This will remove any chance of air pockets to ensure a solid pedal and consistent stopping.

We're not going to give full instructions on bleeding the brakes because if you haven't done it before, it's best to give the task to an expert. Don't take any chances with your brakes because failure will be disastrous.

While the new brakes look great, they also offer a larger swept area to provide higher clamping forces from the four-piston Brembo calipers onto the larger and thicker drilled rotors. The increased surface area will also help to dissipate heat more effectively, reducing the chance of fade.

1. Stock brakes

2. Stock brakes stripped and the hub ready for reassembly

3. New brackets are needed to support the brake lines and ABS cables. They are different on either side. Seen here with stock part

4. Bolt bracket to upright

5. Route cable and lines through the bracket

6. Larger heat shields are needed, seen here with stock part

7. Screw new shield to upright with original T30 screws

8. New 14.6" RS rotors are significantly bigger than 12.25" 2.0T, providing better clamping forces and heat dissipation

9. Screw rotor to hub with original T30 screw

10. Different part numbers are provided for RS and 2.0T 21mm carrier bolts but we found no difference so re-used our originals

11. Tighten 21mm bolts into hub to secure caliper carrier

12. Insert the pads, then secure the bronze-colored spring with greased retaining pins

13. Banjo connector on flexible rubber hose screws into the caliper

14. Other end of hose connects to hydraulic system at top of inner fender. Re-use clip to secure it and change hoses quickly to minimize fluid loss

15. The finished TT RS four-piston Brembo brake upgrade looks and performs superbly

16. We used a vacuum brake bleeder that operated from the workshop airline but there are many DIY tools available

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