DIY: B7 RS4 Front Brake Swap to B6/B7 S4 Full Write Up

[CHECKERED]

This is a DIY guide for upgrading your front B6/B7 S4 brakes to B7 RS4


Table of Contents:

Why is this guide needed
What this guide isn't
Benefits
Drawbacks
Needed and optional hardware
OEM Wheel clearance and Spacers
Difficulty
Installation instructions
Measure aftermarket wheel clearance


Why is this guided needed?

There is incomplete, sparse and conflicting information out there regarding this swap, this guide will help address these problems.


What this guide isn't:

It is not meant to compare which aftermarket kit/brand is better or worse. Please keep the discussion to OEM S4 vs OEM RS4, recommendations for pads/fluids/rotors/lines are welcome.


Benefits:

The Caliper:

The OEM is a 2 pad single piston cast steel with a weight of 17.6lb (w/fluid, pads, bracket,line) it applies force on one side resulting in the inside pad and rotor surface to wear out faster than the outside.
The RS4 is a Brembo 4 pad, 8 piston aluminum monoblock with a weight of 15.1lb (w/fluid, pads, bracket,line), The advantage is having the caliper apply force on both sides of the rotor creating even ware and is lighter by 2.5lb. This is the same caliper used on C5 RS6 and Lamborghini Gallardo.


The Rotor:

The OEM is a traditional cast iron 345mm (13.6") diameter with a thickness of 30mm and a weight of 25lb.
The RS4 is a cross drilled 365mm (14.4") floating rotor utilizing an aluminum hat, with a thickness of 34mm and a weight of 24lb. The advantage is despite being thicker and 20mm (0.8") bigger it weighs less than the OEM but there is a catch, I address this in the next section. Its bigger air gap between the two friction surfaces allows for better cooling and the pad bites into a faster spinning rotor creating more friction and allowing the caliper to apply more torque/leverage.


Drawbacks:

Maintenance cost; RS4 hawk HPS pads are $230-250 while the S4 hawk HPS are under $100.
oem rotors are $140-200 per pair while RS4 are in $650-700 range, even just replacing the friction surface and keeping your aluminum hat you are looking at $450-500.
The caliper is very wide and wheel clearance is an issue.
When you move unsprung weight further away from the axel you end up "loosing hp" or you will put less power to the ground. So pound for pound, the farther the weight is from the axel the bigger the loss. This has to do with moment of Inertia, because the RS4 friction ring is heavier and bigger than the oem ring, you will end up losing hp, If the 1/4 mile time is very important to you and you are doing this swap you must get the lighter weight frictions rings.


What you need to do the swap:

Time:

There is about 2 hours worth of work per side which includes bleeding and trimming oem dust shield.


Tools:

Jack and jack stands
Flat head screw driver
BIG torque wrench
T-30 torx wrench or bit
21mm socket (with various extensions and swivel joint recommended)
10mm socket OR open ended wrench
11mm open ended wrench
If modifying your oem splash shield you will need bolt cutters or a dremel
A minimum of 1 liter brake fluid (2 liters recommended and a power bleeder highly highly recommended)


Hardware: (I included factory part numbers for reference)

RS4 Rotors 8E0615301AB
RS4 Calipers 8E0615107 and 8E0615108
RS4 Pads 8E0698151Q
RS4 Brake Lines 8E0611707H X2
RS4 Mounting brackets for ABS and pad sensor wires 8E0615133G & 8E0615134G
RS4 Small brackets, these secure the brake line at the caliper 4B3615133D & 4B3615134D


Optional hardware:

RS4 Dust shields 8e0 615 311D, 8E0 615 312D
Aftermarket stainless steel braided brake lines (new oem lines are pricey)
4 New caliper to spindle 21mm bolts (these are replaced at dealerships, any brake or suspension bolts that are removed are never reused) but you can reuse you original bolts
2 New brake caliper screws (this is the small screw that prevents the rotor form falling while the caliper is removed) N10648301


OEM Wheel clearance:

If you have oem 18" Avus wheels you will need 10mm spacers with longer 40mm ball seat lug bolts.
If you have aftermarket wheels the only true way to find out is to install the brakes and see, there is an ingenious way to calculate the size spacer you need, I will address this later.
For spacers I recommend once with hub-centric chamfer (ex; ECS or Apikol) rather than universal once (ex; H&R) this will allow for a snug fit and trouble free installation, if the universal spacers aren’t installed just right they will cause vibrations.


Difficulty:

I would only rate this as 2 out of 5, there are some special tools/sockets involved but the most difficult part is removing stubborn bolts and freeing a rusty rotor.


Installation instructions:

If starting with the driver side, turn the wheel all the way to the right, this will make the bolts more accessible.
Jack up the car and remove the wheel

This should look like this:







Disconnect the pad sensor wire, if it's giving you trouble you can insert a small flat head screw driver in between them and at the same time lift the clip.





Using a flat head screw driver push the rubber grommet which holds the ABS/Pad sensor wire up and out of the bracket.





On the back of the spindle there is a 10mm bolt that holds a small bracket and the rest of the ABS sensor wire, slide the rubber grommet out then remove the bolt.





Using the biggest wrench you have remove the 2 - 21 mm bolts that hold the caliper to the spindle. You will need to find the best angle to remove them by using various extensions and swivel joint, these bolts can be very hard to remove, WD-40 spray the night before can help loosen them.





There is no need to disconnect the brake line just yet.


If your brakes are somewhat worn out a lip formed on the outer edge of the rotor and the caliper wont slide out. If this happens insert a tube to the bleeder valve and lead in down to a container, open it using an 11mm open ended wrench, with a flat head screw driver push on the top edge of the brake pad until a gap forms between the brake pad and the caliper, insert the screw drive into this gap widening it, then pull the caliper out, close the valve.





Place the caliper on the ground or on a box, so there is no tension on the brake line.


Remove the small screw that hold the rotor in place with a T-30 torx wrench or bit.


If your rotor is slightly rusty, it will take some force to remove it. Place something under and in front of the rotor to catch it so it doesn't fall on hard ground.
Do not hit the rotor with a hammer you will just damage it.


Place anything resembling a crowbar (I used my hydraulic jack handle) between the back of the rotor and where the caliper attaches to the spindle and pull towards you until the rotor breaks loose.





Using a T-30 torx wrench remove the 4 screws that hold the dust shield.





Either install the RS4 dust shield

or

Install the RS4 caliper to test fit how much the oem dust shield needs to be trimmed, using either bolt cutters, dermal, or even some heavy duty wire cutters and cutting or bending small amounts back and forth until they break, trim about 1" from both ends until it clears the caliper.





Install the new rotor, you will notice that it has two holes for the small screws, but only one will line up to your hub, install the small screw.


As you can see the oem dust shield is just slightly larger than the RS4 rotor.





Prep the Caliper by Installing the RS4 brake pads and brake line with the small anchoring bracket.
Install the RS4 caliper using your oem 21mm bolts.





This is why you oem lines don’t work they bolt up to the hard line at the body, but at the caliper end the RS4 line becomes a hard line and takes a 90 degree turn





Working as quickly as possible disconnect the oem brake line (11mm open ended wrench) at the body and quickly attach the new brake line to the opening, this will minimize brake fluid loss and reduce the amount of air that enters the system.


Install the RS4 bracket to the back of the spindle (reusing your oem 10mm bolt) and connect your ABS and pad sensor wires and brake line this should look like this


Notice how the pad sensor wire goes up and over the bracket





Notice how the ABS sensor goes under the bracket





Another shot from the back





Repeat other side.


Bleed the brakes in this order: Drive side inside valve, driver side outside valve, passenger side inside valve, passenger side outside valve.


If you have oem wheels Install the 10mm spacers with longer lug bolts.


Measure aftermarket wheel clearance:

If you have aftermarket wheels, in order to accurately calculate the spacer that’s required to clear the wheels, purchase some large metal washers, bring a lug bolt with you to test fit the inside hole, you can find these at most home improvement stores. Using tape install 2-3 washers over the lug openings, and install the wheel, increase or decrease the amount of washers needed until the spokes clear the caliper by 2-3mm, 4mm being best . Measure the thickness of the washers, this thickness is the spacer you'll need, you will also need longer lug bolts. oem are 28mm in length + the size of your spacer rounded up. So if you needed a 10mm spacer they don’t make 38mm lug bolts but they make 35mm and 40mm, because we are rounding up you will need the 40mm.





As you can see the caliper does clear the inside of the wheel, with 2mm gap its very close.





Repeat other side.


If using new pads, follow the recommended bed in procedure.


DONE

[trexturk]

those rotors must have been sitting outside for a while.
dont think its a good idea to use them with all that rust

[RAudi Driver]

http://www.audizine.com/gallery/data...MG_1375mod.JPG
What's up with this picture?

[CHECKERED]

those rotors must have been sitting outside for a while.
dont think its a good idea to use them with all that rust

the pictures make them look worse than they are when I washed them off it created a bit more surface rust

http://www.audizine.com/gallery/data...MG_1375mod.JPG
What's up with this picture?

it’s a mirror image, it was taken on the passenger side and I inverted it so that all the pictures appear to be from the drive side, so it's easier to follow step by step, very good eye.

[RAudi Driver]

What's up with this picture?

[JimmyBones]

Very nice write up. It is time to trade up to some bigger wheels.

trexturk, The first good stop will get all the surface rust off.

[trexturk]

i know braking will get the rust off, just seems like a little more the light rust from the pictures. I guess you really cant tell much from pictures.

[CHECKERED]

i know braking will get the rust off, just seems like a little more the light rust from the pictures. I guess you really cant tell much from pictures.

It’s funny that you mention that. when I was negotiating to buy these, I made the seller give me a huge discount because the rotors looked very rusty and I thought they would be unusable. But when I got them there was just a little bit of surface rust, I guess rust reflects the flash from the camera making it look as if it’s deeper and more pronounce, even looking at the pictures I posted they look very rusty.

[ngng]

Nice writeup!

[shokwav09]

do you have these rotor hats numbers please? and terrific writeup on the brakes

[CHECKERED]

do you have these rotor hats numbers please? and terrific writeup on the brakes

Sadly, Audi doesn't make the hats separately and you'll have to buy the entire rotor

[mad70sx]

wow...nice job! Thanks for taking the time to write it up!

Now put some decent wheels on your car so you can show off those RS brakes! Those Avus wheels don't do them justice.

[CHECKERED]

wow...nice job! Thanks for taking the time to write it up!

Thanks, it took 8 times longer to get all the pictures, part numbers, background information and write instructions than to do the swap.

Now put some decent wheels on your car so you can show off those RS brakes! Those Avus wheels don't do them justice.

very true, but also very stealthy (black calipers vs red of yellow) but I recently got new tires on them so I wont be changing for 2-3 years, after that some 19”

[dextrek]

Any impressions on the upgrade?

[CHECKERED]

Any impressions on the upgrade?

Haven't driven the car yet, secretly working on a rear RS4 brake swap

[TEB]

Install the new rotor, you will notice that it has two holes for the small screws, but only one will line up to your hub, install the small screw.

Any chance this will cause a balance issue?

[CHECKERED]

Any chance this will cause a balance issue?

Yes and No
The hole that remains unfilled is in the aluminum hat (small amount and lightweight metal) and very close to the axel, so there probably is a very small vibration on some level but it won’t be noticeable.

EDIT:
I thought about this, and let me answer it another way, with the oem rotor there is only one screw there is no screw on the other side of the hub to balance it out, if that doesn’t cause vibrations neither will this.

[TEB]

Yes and No
The hole that remains unfilled is in the aluminum cap (small amount and lightweight metal) and very close to the axel, so there probably is a very small vibration on some level but it won’t be noticeable.

Thanks for the reply. You're probably right ** if there was a corresponding hole in the hub that wasn't being used it would be a bigger deal.

Couple other questions for a B6 noob: What do a used set of RS4 front brakes typically sell for? Are there any other OEM brakes that bolt up to a B6 S4 ** some Porsche perhaps?

I just replaced my B5 A4 which I tracked requently and was fairly well modded underneath. I'll probably keep this S4 stock for a season and then try to start acquiring suspension/brake parts as opportunities come up.

[CHECKERED]

Couple other questions for a B6 noob: What do a used set of RS4 front brakes typically sell for? Are there any other OEM brakes that bolt up to a B6 S4 ** some Porsche perhaps?

I saw a few for around $1000 for average condition
$800 for lower: rotor needs resurfacing or unusable needs new pads.
$1200: plenty pad life, good rotors.
I was able to get a full set from a totaled RS4 for $1150 shipped fronts and rears (w/pads/rotors/lines/brackets/e-Brake cables) and I need about $150 worth of parts repairing driver side rear.
It’s really just a waiting game until the right set comes along, I have been looking for about 6 months.

You always have the choice to buy new for 2300 +/- 200

From my understanding Porsche six piston Cayenne calipers directly bolt up to the spindle but need different rotors and are only 0.3” or 0.2” bigger depending on the kit, so its not really a “big brake kit” more a “big caliper kit”.

Value wise at $1700 +/- 150 the Cayenne is a close second behind the RS4

[mbgt72]

Any chance this will cause a balance issue?

Just for reference, the JHM lw rotors don't utilize the securing bolt. The only real reason it's there is probably for production line assembly so that it's held in place as everything else is being assembled. But I understand what you're saying, and I gotta agree with checkered, the weight off balance is extremely negligible and not of real consequence.


Thanks for the writeup here too checkered, it's a good little project! I'd be interested to see what difference there would be between the Cayenne kit vs the RS4 setup. For BBK, picking up a set of slightly used JHM Cayenne Rotor Kit seemed like the best deal, but this is certainly a nice option, and may even be a better one (but by the end of everything being done, it seems that a used Cayenne kit may be slightly less if they include everything).

I did have one question though, with the brake lines, are the OEM RS4 ones stainless steel lines or just similar to S4 brake lines? Just curious, as to if there was a SS line upgrade option that could be done at the same time.

[mad70sx]

Thanks for the reply. You're probably right ** if there was a corresponding hole in the hub that wasn't being used it would be a bigger deal.

Couple other questions for a B6 noob: What do a used set of RS4 front brakes typically sell for? Are there any other OEM brakes that bolt up to a B6 S4 ** some Porsche perhaps?

I just replaced my B5 A4 which I tracked requently and was fairly well modded underneath. I'll probably keep this S4 stock for a season and then try to start acquiring suspension/brake parts as opportunities come up.

^^^ Porsche Cayenne calipers will bolt on with a specific bracket and hardware. A couple of companys make kits for this application.

JH Motorsports
http://jhmotorsports.com/shop/catalo...c8b8e86c08b664

ECS Tuning
http://www.ecstuning.com/Audi-B6_S4-...ew_All/ES2538/

[mad70sx]

I was able to get a full set from a totaled RS4 for $1150 shipped fronts and rears

Are the rear brakes on the RS4 different than on the S4? Floating rotor like the front?

[CHECKERED]

I did have one question though, with the brake lines, are the OEM RS4 ones stainless steel lines or just similar to S4 brake lines? Just curious, as to if there was a SS line upgrade option that could be done at the same time.

On the outside they look similar, rubber, but they are stiffer, some people say they are internally stainless steel braided, I will actually cut one open and see, I have stoptech stainless steel lines in the mail, so yes you can get true SS lines, which I recommend because they are cheaper than new OEM RS4 lines.

Are the rear brakes on the RS4 different than on the S4? Floating rotor like the front?

a write up for the rear RS4 brakes is coming soon (3-4 weeks I need extra parts). But to answer your question, the RS4 rear brakes are different, it’s a “semi floating rotor” ...I guess a hybrid between a true aluminum hat floating rotor and a traditional cast iron

[jds4]

great job

[pattrick02]

do you really need those brackets for the abs sensor and ss line or can you use the stock b6 s4 ones? i just ordered a set of r8 calipers, (same as rs4), along with rotors...and hopefully will be installing some time next week, when they ge there.

[CHECKERED]

do you really need those brackets for the abs sensor and ss line or can you use the stock b6 s4 ones? i just ordered a set of r8 calipers, (same as rs4), along with rotors...and hopefully will be installing some time next week, when they ge there.

the bracket holds the brake line so it doesn’t rub against the wheel or a hot caliper, you can use zip ties if you wanted to…but the brackets are only a couple bucks and make very clean oem installation, that’s one of the benefits of doing RS4 or R8 swap rather then getting aftermarket.

[create]

jealous. nice write up. hopefully this will be next mod ( if i can find a set of rs4/r8 calipers/rotors)

[pattrick02]

the bracket holds the brake line so it doesn’t rub against the wheel or a hot caliper, you can use zip ties if you wanted to…but the brackets are only a couple bucks and make very clean oem installation, that’s one of the benefits of doing RS4 or R8 swap rather then getting aftermarket.

thanks for the input...that's true...rs4/r8 is definitely a good choice...i've been mad anxious waiting for everything to come in...it's time for a complete brake overhaul!

ohh, and a little off topic, but how do you like your eurogear vented hood?? did you paint yours? if you have any pics, i'd like to see them, just ouf of curiosity! i installed mine a while ago, but enver painted it..

[CHECKERED]

ohh, and a little off topic, but how do you like your eurogear vented hood?? did you paint yours? if you have any pics, i'd like to see them, just ouf of curiosity! i installed mine a while ago, but enver painted it..

I like the hood, I’m doing a full review with intake manifold temperatures before and after (I’m still collecting data)
I will be painting it, trying to make the car look as stock as possible.

[pattrick02]

I like the hood, I’m doing a full review with intake manifold temperatures before and after (I’m still collecting data)
I will be painting it, trying to make the car look as stock as possible.

sweet...i look forward to seeing the write-up!!!

[mad70sx]

Checkered...what happened with the rear brake swap? Did you ever get that done?

[CHECKERED]

Checkered...what happened with the rear brake swap? Did you ever get that done?

It’s not done, still waiting for parts, the original guide pins that I bought didn’t fit, I contacted the manufacturer and they ordered replacement parts from Audi, which are on back order, I offered to send them my original parts, but they refused saying “stuff gets lost around here” a bunch of idiots over there.

[mad70sx]

It’s not done, still waiting for parts, the original guide pins that I bought didn’t fit, I contacted the manufacturer and they ordered replacement parts from Audi, which are on back order, I offered to send them my original parts, but they refused saying “stuff gets lost around here” a bunch of idiots over there.

lol...nice. Looking forward to seeing this once you get it done.

[OneFastBMW]

Great job on the install. I love the look of a beefy caliper behind the wheel. It makes people think their might be something different about this car and that it is not just some A4.

I have the JHM kit using the Porsche calipers and I love them. JHM makes some great, quality stuff.

Having said that. If I were doing the brakes again I think I would do the RS4 kit for the followings:

These Calipers were made for this chassis so it is a cleaner install

No need to modify pad sensors

Use of OEM brake lines so easy to get replacements

Also, I would get the JHM "Big" rotor rings for 380mm brakes up front.

[pattrick02]

Great job on the install. I love the look of a beefy caliper behind the wheel. It makes people think their might be something different about this car and that it is not just some A4.

I have the JHM kit using the Porsche calipers and I love them. JHM makes some great, quality stuff.

Having said that. If I were doing the brakes again I think I would do the RS4 kit for the followings:

These Calipers were made for this chassis so it is a cleaner install

No need to modify pad sensors

Use of OEM brake lines so easy to get replacements

Also, I would get the JHM "Big" rotor rings for 380mm brakes up front.

380mm....i'm wondering if those will clear my 18" TDR's

[CHECKERED]

Also, I would get the JHM "Big" rotor rings for 380mm brakes up front.

There are many drawbacks, to the 380mm setup

First, they don’t fit under 18's
Second @ $650 for just friction rings is a bit much
You “loose power” by moving mass to the outside of the axels
The oem RS4 setups is sooooo money, I have yet to find the limits, I’m limited by my tires overheating long before the brake do.

[sakimano]

awesome write up Checkersauce

This would be a nice thing combined with JHM's RS4 LW rotors, which shave even more weight off vs. S4 stockers.

Not the big monsters...just the OEM RS4 sized JHM LW rotors. Can't see them on their website right now though. I believe with those you can just swap rings as you burn them out, so the cost should be pretty similar to OEM rotors.

[CHECKERED]

Can't see them on their website right now though. I believe with those you can just swap rings as you burn them out, so the cost should be pretty similar to OEM rotors.

it's there:
http://jhmotorsports.com/shop/catalo...f39dd5df4d5f92

I mean when comparing the cost between oem size lightweight rings and 380mm its $160 bump for just 0.6" bigger, when the limiting factor in most setups are the tires not the brakes, unless one is running road racing slicks

[AudiA4_20T]

quality writeup

[sakimano]

it's there:
http://jhmotorsports.com/shop/catalo...f39dd5df4d5f92

I mean when comparing the cost between oem size lightweight rings and 380mm its $160 bump for just 0.6" bigger, when the limiting factor in most setups are the tires not the brakes, unless one is running road racing slicks

I don't mean those giant ones...I mean the OEM sized, JHM LW RS4 rotors. Where'd those go? they used to have them.