Avant Rear Brake Upgrade - Rear Brake Porn by request

[Jamo]

Sexy brakes!

Damn put on my wish list!

[MattS2]

Having experienced the sheer power of these brakes from the passenger seat,
all I can say is WOW!

Regarding the suspension overhaul, the car felt absolutely planted at 65mph on the motorway and felt like it could easily handle another 100mph on top of that.

I too have safety concerns though.

Has there been any mods. to the brake pedal to gain the extra travel required?


Matt.

[Corey]

Nice, simple and effective.

Good work Ben

[s2avant]

The master cylinder is coping just fine.

It's everything (and everyone) in the car that suffers when you stamp on the middle pedal :mischeif:

Carly has already complained that the seatbelt hurts her shoulder when I give the brakes a workout.

The RS4 rear setup should also fit but would need even more length on the handbrake cables. I'm thinking about trying the 335mm W12 phaeton setup next. Maybe when the rear pads need changing

Got lots of other stuff to do first though.

Ben

[4WheelDrifter]

Good write-up Ben. Shame it's not much use to Coupé owners.

Yes. They would look a little small, if they were front brakes.



BTW, how is your master cylinder coping with all this modification?

[NEO]

Wonder what the difference is to the coupé regarding hand brake cable. What did the calipers cost?

edit... Oh btw... If S4-b7 fits RS-b7 fits to. =) Know that a guy here in sweden had RS4a calipers on his S4. Same guy I bought my RS4-b7/RS6 front calipers from.

[s2avant]

Ok then, I've had this setup on my car for a while now but as it has been hiding in the garage having even more tinkering done I haven't got round to sorting the thread out.

We have replaced my original upgrade B5 S4 256x20mm setup with the 300x22mm rear disc setup from a 2007 B7 S4. the best part is that it is a simple bolt on upgrade. As such there is not a lot to write about it.

Here is a comparison of the old and new discs:


As you can see there is not a huge difference in diameter but after switching to the 256mm setup from the standard 245mm I can say there was a considerable difference in braking ability. The step to 300mm has brought a similar increase in stopping power.

As I said above it is a simple bolt on affair:


The only challenging area were the rear back plates and the handbrake cables.

We did start with the B7 S4 rear back plates but they weren't really a feasible fitment as the mounting holes were too big and in the wrong places. Instead we tried the B5 RS4 back plates which after some fondling by the wizard worked perfectly. They aren't cheap though and you do have to cut them a little to give clearance for the caliper.

Here is the cut needed above the caliper:


and here is the one needed below:


The last bridge to cross was getting the handbrake cables to fit. The solution to this proved to be very simple indeed.

On the cable the limiting factor to the length is the clamp on section which supports the cable where it goes through the lower arm:


By loosening the metal clamp and cutting back a portion of the rubber shroud we we're able to move the section back down the cable to give enough free length to fit the caliper.

Here is a side by side view so you can see how far it needs to be moved:


As you can see it doesn't need to go far. One side effect of this is that the cable will not fit into its bracket by the fuel tank anymore. Instead it overlaps the corner of the tank:


The two threaded studs towards the top of the image are where the original clamp fits. I'm sure this is going to get some people questioning the safety of my brakes once again but there is plenty of clearance between the cable and the ground so it won't get caught and it doesn't move so there isn't a problem with it rubbing.

So there you have it. I think they look too small behind the wheels though :


As I have mentioned previously this conversion combined with the suspension work that was carried out at the same time has virtually eliminated nose dive from the RS6 front setup. I couldn't say which has made the most difference though as every single nut, bolt, washer and bush in the whole suspension setup has been replaced with polyurethane or alloy versions or where they aren't available with brand new OE parts. This has made the whole car much tighter and I would thoroughly recommend it on an Avant as there are a lot of bushes which can get tired in the rear suspension. NVH has increased considerably with the components I have chosen but even new OE bushes would transform a car.

Ben