audiphobic

'01 2.7T. Car has been shaking miserably during braking for some time now. Especially when they get heated up. Need to replace rotor/pads.

How does one tell the size of the front rotors and the correct caliper for pad replacement?

What seems to be the best combo? Drilled/slotted/solid rotors?

Thanks in advance.

MCH 2.7t

Re the vibration, read the info on the link below. You may be able to solve your problem by re-bedding your brake pads.

If you end up replacing the pads/rotors, StopTech has a reasonably priced slotted stock replacement rotor. The slots help to keep the face of the brake pad clean. Drilled rotors are generally not recommended as the holes can induce cracking.

Rotors come in 2 offsets for our cars. You'll need to measure yours to determine which you need.

<img src="http://pictureposter.audiworld.com/68483/rotor_offset.jpg">

You likely have the HP2 caliper. You can find a variety of pads for this caliper. Check the technical section of the pure-motorsport.com site for a listing and attributes of different pads.<ul><li><a href="http://www.stoptech.com/tech_info/faqs.shtml#25">http://www.stoptech.com/tech_info/faqs.shtml#25</a</li></ul>

Stoney

1) You don't have to measure your rotors to tell which you have. Just call the parts department with your VIN and ask for the part numbers for rotors and pads.

I am one of the late 2001 4.2s that have the odd sized rotors, the 22.7mm offset. You will see that the order page for DBA rotors calls out a special part number for this size. <a href="http://www.awe-tuning.com/pages/shared/part_detail.cfm?PMaI=1&PMoI=28&PEI=6&PP=a6_27t_bra kes.cfm&PPT=Brakes&IL=a6dba">AWE Tuning - DBA rotors for A6 4.2</a>. <a href="https://forums.audiworld.com/a6/msgs/548208.phtml">Part numbers for 22.7 mm rotors</a>.

If you are in the majority and have the 16.7 mm offset rotors, then you have more options. I believe Stoptech does indeed have a drop in replacement. Zimmerman also.

2) Audi rotors do indeed warp. As you observed, they are worse when hot, something that points to warpage. Don't let that Stoptech article about it being a "myth" mislead you. Audi rotors don't ventilate properly, hence they overheat and warp. Still, it can't hurt to do the bedding procedure described by Stoptech and see if your vibration goes away. Mine didn't.

3) You don't need brake upgrades unless you want better pedal feel or lower unsprung weight. The calipers you have are capable. See posts in the FAQ about BIRA, who tested them extensively. You can instead just get new rotors. BIRA is one source, the Coleman Replirotor. However it is pricey the first time you buy them (cheaper thereafter). I bought DBA rotors which are designed specifically to ventilate better.<ul><li><a href="http://sonolithics.com/files/a6_links.html#brakes">http://sonolithics.com/files/a6_links.html#brakes</a</li></ul>

cdn A6 4.2

My 10/99 build '00 4.2 also has the 22.7mm offset rotors