mug23

I have a 2004 Allroad and have the single piston caliper. I really like to see if I can upgrade to the S4 HP-2 caliper and want to see if it's a direct bolt on for my 04 model year? I know the older Allroad did come from factory with this caliper.

Thanks.

5v/cyl

Should be bolt up, but will require new caliper brackets and maybe different rotors.

Your current setup will have very good braking with the right rotors and pads, assuming the rest of the brake system is in good order. Flush your fluid out with new fluid which will also get any possible air bubbles out of the lines to increase pedal feel. Then install a set of Zimmerman Z-coat rotors with Akebono Euro pads. This rotor/pad combo is amazing when properly bedded in. You can further improve braking by doing the rears too with a high quality rotor and the Akebono's again.

I did this to my wife's AR and did a proper bed in of the pads. Next time she drove it she couldn't believe how good it stopped and took some getting used to to stop smoothly and not to quick.

mug23

Thanks for the reply. I hopersonally someone here have experienced going from the single piston caliper to hp-2 and see if I can use the current rotors I have for the single pistons? If not, which rotors can I use?

5v/cyl

Looks like same rotors and actually the same brackets as well according to: allroadFAQ.Com