I would like to replace the front rotors on my 2003 A6 4.2L but unfortunately the Bentley Repair and Service manuals lack any technical information whatsoever regarding this procedure...unless I a just really really dumb and can't find it.

Car is equipped with the Lucas HP2 two piston calipers.



What is the best way to remove the caliper to enable removal of the rotor? Searching around online I find discussions on three different comments but no conclusive direction.

Option 1 (see picture below) - internal hex with the bleed screw in the way on the top. Seems this would only remove the carrier and not enough to pull rotor.

Option 2 (see picture below) - guide pin. I didn't even remove the cap on the back of the rubber boot because I was not sure what messing with this would do for me anyway.

Option 3 (see picture below) - 21 mm hex head bolt. I believe removing these will enable me to remove the entire caliper. If so how do you get them off. The top on pictured is block by the cable sensor connector bracket. The removes with a 13 mm socket but does not really pull away to get good access. I can get a socket on it but no way would I be able to get an impact on it to loosen.



This doesn't look like it's going to be an easy job. Anyway, while I am in there should I be adding some sort of lube to the guides?

 

Uncap the guide pins and remove them so you can remove the caliper from the carrier. Hang it from the spring. Using sturdy wire. Then take out the two big hex-head carrier mount bolts and remove the carrier. Then you're free to replace the rotor.

 

just did mine (i have the exact same setup as you). all i did was remove the 21mm hex bolt. to remove the bolt, I just used a wrench and a small breaker bar for leverage. total time for the job (both sides) was about 1 1/2 hours.

my opinion, option #1 would require a brake bleed and option #2 is a complete waste of time.

 

Thanks guys. Maybe I'll try one each way just for the hell of it.

 

I just had the same issue and removed the bottom 21mm bolt and pulled the caliper clear of the rotor by pivoting the caliper with a pry bar inserted between the rotor and the caliper. I had to get the caliper back in place by using a 4 pound sledge and a piece of wood. It was difficult to align the bolt with the hole but managed by using the pry bar to pull the caliper back after overshooting the hole.