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Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

Our Audi TT gets a TT RS big brake conversion

Greg Emmerson
Jul 13, 2013 SHARE

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.

01 audi TT big brake conversion Photo 2/26   |   01 Audi TT Big Brake Conversion

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.

02 audi TT big brake conversion TT RS brake conversion parts Photo 3/26   |   Our short list of parts for the TT RS brake conversion

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.

03 audi TT big brake conversion Photo 4/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

04 audi TT big brake conversion stock brakes Photo 5/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

2. Stock brakes stripped and the hub ready for reassembly

05 audi TT big brake conversion stock brakes stripped Photo 6/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

06 audi TT big brake conversion new brackets Photo 7/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

4. Bolt bracket to upright

07 audi TT big brake conversion bracket Photo 8/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

5. Route cable and lines through the bracket

08 audi TT big brake conversion cable and lines Photo 9/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

09 audi TT big brake conversion heat shields Photo 10/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

7. Screw new shield to upright with original T30 screws

10 audi TT big brake conversion heatshield Photo 11/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

11 audi TT big brake conversion RS rotors Photo 12/26   |   11 Audi TT Big Brake Conversion RS Rotors

9. Screw rotor to hub with original T30 screw

12 audi TT big brake conversion rotor to hub install Photo 13/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

13 audi TT big brake conversion carrier bolts Photo 14/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

14 audi TT big brake conversion caliper carrier Photo 15/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

15 audi TT big brake conversion pads Photo 16/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

16 audi TT big brake conversion banjo connector Photo 17/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

17 audi TT big brake conversion hose Photo 18/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

18 audi TT big brake conversion TT RS brembo brake upgrade Photo 19/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

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

19 audi TT big brake conversion vacuum brake bleeder Photo 20/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

Wheels

Once the brakes were fitted we wanted to test the clearance of the wheels. With the larger TT RS calipers, we were unsure if the 19" Turbo Twist wheels from the Audi Genuine Accessories catalog would clear them since they weren't designed for this application.

20 audi TT big brake conversion vacuum brake bleeder Photo 21/26   |   19 Audi TT Big Brake Conversion Vacuum Brake Bleeder

As it happens, the wheels wouldn't turn and were hitting the calipers so we had two options. Some H&R Trak+ wheels spacers and longer bolts would definitely resolve the problem - they provide a number of different thicknesses but we ordered the thinnest 3mm spacers that would easily do the job. The longer bolts ensure the wheels are fastened correctly. This is by far the cheapest option.

A second option was to fit different wheels. Obviously this is the more expensive option but if you're looking to upgrade to 19" wheels anyway, this might be the perfect time.

With our TT RS brakes, the logical conclusion was that the same car's wheels would clear its own calipers. However, the TT RS uses the same 19x9" ET52 wheel dimensions as the ones we already had. Undeterred, we borrowed two different TT RS wheel options from our local dealer to test fit and found that both fitted. The slightly different design of the wheel spokes provided the minimal clearance we required and so we decided to order a set of the genuine TT RS "5-arm-rotor" wheels from the dealer.

We have to admit we love the new wheels. The textured, matte, gunmetal finish on the spokes and rim is contrasted by the machined highlights. The effect is stunning and the quality is impeccable, as you'd expect.

The silver split-spoke wheels we tried were also a great looking option. In the end we felt the bright silver finish didn't suit our car as nicely. Yet it's a matter of personal taste since both options cleared the new brakes.

It's worth noting that you need to order center caps separately for some reason but that a matching gunmetal cap is available and the part number is listed below. You'll need to order four.

When it came to tires, we didn't want to fit the wide 255/35 tires from the RS model, so we stuck with the 235/35 R19 Continental ExtremeContact DW tires we'd previously used, to avoid rubbing issues and additional cost. Since we had no issues to date we knew this would be a simple solution.

1. Sadly, our 19" Turbo Twist wheels fouled the new calipers

21 audi TT big brake conversion turbo twist wheels Photo 22/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

2. We selected two 19" wheel options from the Audi Genuine Accessories catalog to try

22 audi TT big brake conversion audi genuine accessories wheels Photo 23/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

3. A cheap and simple solution would be 3mm H&R Trak+ spacers

23 audi TT big brake conversion HR trak spacers Photo 24/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

4. The split-spoke wheels look good and cleared the new calipers

24 audi TT big brake conversion split spoke wheel Photo 25/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

5. We opted for the genuine 19x9" TT RS 5-arm-rotor wheels finished in gunmetal, with a set of matching center caps

25 audi TT big brake conversion TT RS 5 arm rotor wheel Photo 26/26   |   Project Car: Audi TT 2.0T Big Brake Conversion - Part 3

Part
Part #
Number Required
Price (each)
Caliper
8J0-615-107
1
$1340.91
Caliper
8J0-615-108
1
$1340.91
Rotor
8J0-615-301-E
2
$245.00
Pads
8J0-698-151-H
1
$530.00
Hose
8J0-611-701-F
2
$165.65
Shield
8J0-615-311-E
1
$99.00
Shield
8J0-615-312-E
1
$99.00
Bracket
8J0-611-841-D
1
$88.05
Bracket
8J0-611-842-D
1
$88.05
Caliper bolts
N-908-768-02
2
$7.34
Pad Sensor
8J0-615-437
1
$76.34
Total
$4080.26

Additional Parts Used

Part Supplier Part # Price (each)
3mm Trak+wheel spacers (pair) H&R Suspension 0655571 $68.95
Longer wheel bolt H&R Suspension 1453503 $4.45
19x9" TT RS wheel Audi 8J0-601-025-DB $864.00
Gunmetal center cap Audi 8T0-601-170-A $42.66
235/35 R19 Conti DW tires Continental POA

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Sources

H&R Suspension
888-827-8881
http://www.hrsprings.com
Audi Genuine Accessories
http://www.audiusa.com
By Greg Emmerson
1075 Articles

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