chewy8000

In an effort to dispell all the mystery and false information on this issue I'm documenting the whole process in steps with pics. This is on a stock 1981 US non-s car. I simply mocked up the setup this evening and here is what I found.

1: Whoever suggested to change or check the front wheel bearings was correct and I appologize. You cannot remove the dust shield withough removing the hub and bearings. The 993 (NON TT) crossdrilled rotors also did indeed run into the dust shield so I removed it.

2: The stock bolts that hold the stock caliper and are used to mount the adapters are too long and I will be obtaining the correct size tomorrow.

3: The 993 rotors are NOT hubcentric to the hub, they are actually a little larger but once the two beveled set screws are locked in place it centers itself and I don't see this being an issue with a little locktight and the lugs torqued to spec. Everything should hold in place snug under normal driving conditions.

4: I ordered stainless brakelines for an OB and not and S4 so that won't work since the connection at the S4 caliper is a block style fitting instead of a threaded style. Those will get sent back.

Here are some pics I will go step by step tomorrow. The good news is the adapters, rotors, and calipers fit perfect all bolted up. I will need to figure out what to do with the dust shield.

mark kibort

looks great . those rotors look larger diameter than S4, are they? near 13" rotors have 4 and 5 hole rows, and the S4 rotors have 3 and 4 hole rows like the picture shows, BUT, the pad runs real close to the hub and this one looks like it has more room.

mk

JHowell37

It the threads match up and the length of the hose is correct, I think you can get away with those lines.

Chuck Schreiber

Chewy,
Sorry I was late with these, it might have helped had i got them to you BEFORE you did the upgrade. (Maybe it will help someone else doing this)

Dug up some pics from the 2004 OCIC where we did the upgrade as well. You had the 81, so it was a little different. I retained my stock spindles and just went with:
Painted Calipers off an 89 S4
Adapters from DR
New brake lines
New rotors and bearing
All new mounting bolts
New S4 Dust Shields

I pretty much just posted the whole folder I found, so sorry for being so pic intense. Hopefully someone can get some details out of the pics themselves for future upgrade.

chewy8000

Mark the rotors I used are actually 993 rotors not S4. I can measure them when I get to the shop. Thanks for the pics Chuck! Looks like I need to order some S4 dust shields.

Fabio421

The stock caliper bolts are not too long for the adapters. Thats what your supposed to use.

BTW, great pics.

Leon Speed

Yes, on the front calipers (and it requires copper crush rings as you know).

Nice pics, good luck with the install (and bleeding - that's always a pain).

Andre Hedrick

Nope, lemme get some pictures of mine on the car with the cut outs.

SharkSkin

The problem is not with the radial bolts that go through the caliper, the problem is with the lateral bolts that hold the adapter to the spindle. With OB brakes the lateral bolts go through a clearance hole in the spindle and a clearance hole in the caliper, then thread into nuts welded to the backing plate. So, they are too long. They run into the S4 backing plate. You could drill the backing plate or cut the bolts to length, but really it's best to just get the right length bolts.

I'm finishing up my own writeup on this... what was the bolt length that you used? I seem to recall 35mm but I'm not sure. After seeing Chucks pics I see I need to dive back in there so I could just measure them at that time but it's easier to ask.

Actually that's a GREAT help, Chuck... I never thought to put the backing plates on the wrong side of the car to clear the ball joints! Beautiful. I need to get back in there and mount up my dust shields. I was going to cut a hole like Andre is talking about but your solution looks much simpler. I'll have to add this info to my writeup.

Fabio421

I used the stock bolts on mine. But I tossed the dust shields. Is that what you are calling "backing plates"?

SharkSkin

Yes, that's what I meant. Showing my age I guess.

And yes, without them it will work.

Andre Hedrick

Here is a photo of my cut outs.

chewy8000

I got the right S4 stainless brake lines in today and finished up the fronts.



Here are the correct bolts I found at Auto zone.
They actually come with nuts that you can install on the back of the adapter for further security.



The adapters didn't quite fit exact and I had to grind a little of the top mount to clear the adapter.



Here are the adapters bolted in with the hardware from autozone.
You can see you can easily fit the nut the bolts come with if you would like some extra peice of mind.



Rear will be tackled ove the next few days. I haven' painted the caliper like I intended until I make sure they are functional with no leaks. Once they past the test they will get some gloss black treatment.

chewy8000

I got a chance to wrap up the conversion today and bleed the system. Everything turned out great and I can wait to test the new setup. One concern I did have though was how close the front 993 rotors are to the lower ball joints. They don't actually touch but man are they close!

Fabio421

That looks like the alum. ball joint. Can you confirm? If so, they need to be changed. I believe the steel ones give a little more clearance.