Rocky Mountain Club B5

Discussion Forums => Maintenance => Topic started by: 03Indigo on March 02, 2004, 10:10:10 AM

Title: HP-2 Rotor and Pad replacement, for B5 S4's and other 2.7Ts
Post by: 03Indigo on March 02, 2004, 10:10:10 AM

Now that the disclaimer is there......This is an accounting of my experience in replacing my front rotors and pads on my 2001 allroad 2.7T.  This reviews the HP-2 Brake set up, and most likely is different for the 2003 and later models of the Allroad.  (the HP-2 4-pad caliper set up is identical to the Audi S4, A6 2.7T, and A6 4.2).  I referenced the article written in 2002 by Mark Quinn.  It can be found in the tech section or at this URL...

That article was helpful in getting me started, but the rest I figured out on my own.

Here is a list of tools I used.

21 mm socket and 1/2Ē socket wrench with extension bar
small flat head screwdriver
small pliers
trash can
2 c-clamps
wire cutters
wire connectors
anti-brake squeal sticky stuff
brake cleaner

Ok, I think that is a list of what I will see most of the tool in the photos that follow, so bare with me.

To start....I ordered my Zimmerman Cadmium coated slotted and cross drilled rotors from  I also got a complete set of PBR ceramic brake pads.  This set came complete with all 8 pads there were needed for the front brakes...please note, these are for the front brakes only...including brake wear sensors.  Their fitting is different than the OEM Audi plug, but an easy splice of wires allows you to use the OEM plug in place of what comes on the PBR pads.  I will get to that later in the write up.

Here is a picture of the new rotors, and the new pads, and my DVís, but those are not part of the brake install.  Arenít they nice and shiny :-)


Once you jack up the car, (please refer to your owners manual on how to do this, as you need to prep the car for jack mode as not to damage your air suspension components), you then remove the front tires.  This is what you will see, the OEM set up


In following Mark Quinnís write up, you need to remove the retaining clips for the brake pads, this is quite easily done with a small pair of pliers to grab the wire.  Here you will see the retaining clip in place, then removed and rotated 90 degrees.

Retaining clip in place

Retaining clip removed and rotated

This is where I differed from Markís write up...I did not compress the pistons at this point, I instead found the 21 mm bolds on the back of the caliper and removed those...there are 2 of them.  They are fairly easy to get to when using the socket extension.  Once those bolts are out, the entire caliper and rotor are free of the car.  I carefully slid the rotor off the hub, and then pulled it out of the caliper.  I set the caliper on an office sized square trash can that was on itís I would not place any stress on the attached brake lines and sensors.  You will see this in photos further down.  Sorry I did not take pictures of the bolts to remove, but you will see the general location of the top 21 mm bolt.

Here are a comparison of the old rotor to the new rotor, and the old pads to the new pads



At this point, I compressed the pistons in the calipers so that it would be ease to put the new pads in around the rotor.  I used 2 C-clamps, but Mark wrote a different way to do it.  i would recommend using 2 clamps.  When you do this, take the cap off the master brake res, then I packed paper towels around the top of the res to catch any over flow while I did this.  As it was, I has zero overflow, but my brakes were just serviced at my 40K service.  When compressing the pistons, go slow, check for overflow, and remove any excess fluid as needed.  Here is how I placed my C-clamps to compress the pistons, and a picture of the pistons compressed.

Clamps on the pistons

Pistons Compressed

At this point, I put the new Zimmerman rotor on and replaced the caliper but bolting it back in place with the 21 mm bolts, but not tightening it down as of yet...I wanted to leave some play to get the pads in place.

assembled new stuff :-)

then I decided to put on the anti-squeal red sticky stuff on the new pads.  I just copied where the stuff was on the old pads.

At this point, I decided that tightening the 21 mm bolts would be in my best interest, so I did.  Here you can see the 21 mm socked, extension, and bolt.  This is looking straight down on the top of the caliper.

Doing this actually made it easier to slide the pads in place.  Which is what I did next.   I paid special attention to put them in on the right sides.  The inner pads are different from the outer pads, and one of the inner pads has the wear sensor...which goes on the inside top part of the caliper.


once they were in place, it was time to return the retaining clip.  With some handy dandy dexterity, I was able to take a picture of me holding the clip with the pliers and take a picture at the same time, ainít I the talented one?


Now comes the electrical part.  The plug that comes on the PBR is different than the OEM some splicing needed to be done.  This info is on the ECStuning site, so it was not a surprise, I knew what to expect and was ready for this.  I cut the old plug off and spliced it onto the new pads.  easily done with some crimps, and I will cover it with electrical tape to seal and protect the connection.

In this picture you can see the old plug on the left, the incorrect new plug on the right.

here is a close up of my splice

and a close up of the wear sensor plug attached and returned to itís original position with the wire returned into the clips.

one last close up of everything back where it belongs, pads, retaining clips, wires, and the rotor all shiny :-)

and now the job is done.  Put the cap back on the brake res, apply the brakes until you have resistance, this took about 4-5 full pumps of the brake...then it had a solid feel.  Repeat this process for the other side, and when all is said and done, check the brake fluid level, add fluid as needed before heading out on the road.  Follow the proper brake pad seating procedure to ensure maximum performance and life from your new rotors and pads....oh yeah, donít forget to put your wheels back on...hehehe.

last shot of the Zimmermans
Title: HP-2 Rotor and Pad replacement, for B5 S4's and other 2.7Ts
Post by: ColoradoB5 on March 02, 2004, 10:57:36 PM
Wow!  Jon, now with the brake rotors that nice, you need to get those calipers painted.
Title: HP-2 Rotor and Pad replacement, for B5 S4's and other 2.7Ts
Post by: 03Indigo on March 03, 2004, 07:19:05 AM
I thought about it for a while, but with all the gaskets, rubber dohickies, and size of it, I passed.  I had fully intended to paint them bright silver when I did this brake job, but once I saw how complex they were, I passed.  I did not want to mess up a seal and have to replace one of them, that can't be anything but outragiously exensive.

jon 8)