Jretal

Hey guys,

So as we finally got the '83 running nicely for the most part (still getting hesitation at around 4500 rpm at WOT, but once that point it'll take off again), we run into another issue. The driver's front caliper is pretty much seized. All pads on the car are near new, but that side got eatten down to the backing plates. We knew there was a dragging caliper, but I thought it was the rears due to the parking brake. Boy was I off... lol.

When I went to go retract the piston in that caliper it won't budge. I fought it for a little bit, but it just isn't moving. The boot is intact, but it looks like it pulled 'out' in a few spots allowing water/moisture to get in.

Instead of rebuilding that caliper, we're upgrading. This car will be seeing a bit more power once we 20vt it, so I figured why not put bigger brakes on now instead of spending it twice. I scored a set of A4 calipers for cheap and want to toss them on w/ the regular 288mm rotors from my A4 (I have my old ones left over from when I upgraded to the D2 A8 rotors), and will later upgrade it to the D2 A8 312s with the TT carriers.

What I need to know: Is there anything I need to do to get the A4 calipers to fit on the upright? I have a hunch that we might need to space them back w/ a washer or two, but other than that... are there any difficulties getting these on the car?

I'm pretty sure they'll fit under the 15" R8 wheels, but are there potential fitment issues that any of you know about?

Thanks all! We need to get this car rolling again before my mom kills us... lol. For the few months we've owned it, it's spent 3/4 of that not running properly... lol. Welcome to the UrQ club, right?

4x5x5

<center><img src="http://pictureposter.audiworld.com/53330/bigbrakes_002.jpg"></center><p>AFAIK they won't fit with your 288 rotors, wrong offset. You'll need carriers from an early TT, that's what makes the set up work on UrQs and typ 44's (provided your A4 calipers are of the same vintage as the TT)
Then you need the 312?mm from the early A8. Then you'll need 16" wheels.
See my pix poster for pix

Jretal

it just pushes the caliper further "away" from the hub... and the A8 rotors thus have the same offset as the A4 (I've had them side by side before) w/ my A4. I'm 99% sure of this.

Also, I got confirmation via email from a lister that the stock A4 setup will fit on the car and fit behind the stock wheels, which is a bonus.

I just need to find a set of bleeders for the A4 brakes since someone snagged them for some strange reason... and they came with a set of 1/3 used pads, so that means less $$ dropped on something that'll be replaced down the road :-P

4x5x5

"it just pushes the caliper further "away" from the hub... "

This is the definition of offset. If one carrier pushes the caliper in either direction from center, the offset is different and they are not interchangeable with the same rotor.

Jretal

it pushes it away from the center of the hub... as in if you take the center point of the caliper when looking at it from the side, when using the TT carrier it creates a greater diameter vs the A4 carrier.

Offset (as in closer to the wheel/fender lip or closer to the suspension/motor) I *believe* is the same... but I'm going to have to go double check this so I'm not posting incorrect information!

4x5x5

I thought of that after I hit send. You mean "radially' not 'laterally'. Either way keep us posted, when I did a GB of these components we found the A4 carriers did not work, I believe ECS also sells the kit with TT carriers. Since the whole point is for more braking power I can't say I recall ever checking the stock rotor but seem sure the lateral offest differences called for the A8 piece. That said if the caliper uses the same pad in both applications, it may work.

Jretal

The obvious difference w/ the A8 vs A4 rotor is that the A8 is 312mm vs the A4 288mm. The only reason you can't use the TT rotor is because the lug spacing is 5x100 vs the 5x112 on the A4, A8, etc. All the pads and such stay the same since you're using an A4 caliper, and the carrier/rotor have no affect on the pads.

I will see if I can take the rotor off the 4000 (A8) and compare it to the stock rotor off my A4 and get some pix to give a visual confirmation on the offset.

4x5x5

the 97-2000 era A4 rotor and same era A8 rotor have the same offset, just that that A8 hase the 'better' size.

Jretal

btw, that includes '96 as well, as that's what my A4 is

Thanks for confirming that... now I don't have to take the 4000 apart to get the rotor off and compare :-P