replacing front rotors (HP2 calipers). do i remove 2x 21mm bolts or the 7mm ones?
 

searching the archives. the A4 tech article shows removing the plastic caps to access the 7mm bolts to remove the caliper. something tells me that's not right for the A6/ar (now that I look again, the bolts under the plastic caps don't have a hex, int or ext, on them). However, i can't get those 21mm bolts to budge. I only want to get the rotors off, not replace the caliper. help, please.

messy job, by the way, geez

You need to remove at least 1 of the 21mm bolts.
 

if you can't get both, you can generally swivel the caliper on the stuck bolt. " very hard to remove" is very typical

You're not kidding they're tight!
 

My upper body ached for days after doing the HP2 swap. (no air tools, and I'm a skinny guy :)

I separated a rib!
 

<center><img src="http://www.micom.net/oops/WomenLiveLonger1.jpg"></center><p>Well, using your chest as a platform for a breaker bar should qualify for a Darwin award.

well I gave up. w/o a lift I can't get enough travel with a breaker bar to loosen them.
 

Guess I'm paying an installer. Grrrrr.

Did you try turning the wheel completely one way or the other? Might give you enough travel.

I may try again tomorrow. too pissed off now. :)

rare that you can't phase the socket on the breaker....
 

to get the right position to crank on the bolts. What I'm saying is that if your socket isn't providing enough travel, take the socket off the breaker and rotate 90. Common issue.

Where are you located? Perhaps someone can lend a hand, finger or rib.

You need a ton of leverage
 

Get the biggest ratchet you have and hit the end of it with a mallet. They come loose. Just grease them before you reinstall. I did mine a few weeks ago.

I like the mallet idea, but... grease?
 

Do you perhaps mean antiseize?

Grease before install: use proper Anti sieze....
 

Get into this habit now. I am now to the point where i'm ripping into areas where i've previously worked, and gosh is it nice when there isn't any stuck bolts despite years of mag chloride attack.

I used a small breaker and a large wrench @ 90 degrees. Worked perfectly.

thx for the suggestions folks. gotta get some anti-seize, bigger breaker, and try again next week.
 

i only pulled a couple of the pads on the front side out, so i just put everything back and pumped the brakes to set the pads back.

As an aside, it gives me a chance to get some good brake cleaner too. When I bought the ar last year, it had a torn cv boot on that side an had slung grease all around that area for some time. The boot is fixed now, but the grime is coated pretty thick.
Without disconnecting everything, what's the best way to get to that 90% clean level?

I used a large pipe and leveraged it perpendicular to the breaker bar.
 

For the left side use something like a hockey puck to protect the underside of the car so you can leverage against it.

not too many hockey pucks down here in Atlanta, but I'll find something. :)

Encountered same thing. Hit it w/ PB Blaster, walked away for couple hrs, dinner, swimming, came
 

back, success. ;)