atb

Can someone provide the part numbers for the front rotors to be used with the OB brake caliper adapters when running an S4 (NOT BIG RED) front calliper?

Thanks. I found out today that the S4 rotors have too much offset. Should have searched the issue BEFORE assembly.

Andre Hedrick

They are 993 parts, I don't have the number but I bought them from 928Intl.

tlsmith1999

These are the ones I ordered from Roger for my 78, with S4 brakes, and the adapters:

1 X Drilled Rotors S4 Upgrade Right 993 351 044 01
1 X Drilled Rotors S4 Upgrade Left 993 351 043 01

Fabio421

Nope, the S-4 fronts are what you want. You may find that they rub on the ball joint. This seems common.

atb

Here's what the contact with the ball joint looks like, it almost looks like it could work.



Just for kicks I tried to shim the rotor. I put two 2mm washers between the hub and the rotor and that gave me enough clearance for the ball joint.



But, the rotor was still too far inboard in relation to the caliper.



When I saw this I knew that I was dealing with the wrong brake disc.

Thanks for the part #'s Tim.

Fabio421

So your having issues with the caliper not being centered on the rotor. Hmmm? This may sound like a really stupid question, but, are you sure you have the adapter bolted up correctly? Post a pic of the adapter please.

atb

I have the adapters oriented so that they are hanging on to the outside of the spindles, the machined recess facing in and the flat surface facing out. I tried it the other way, but it positioned the caliper so for out that they wouldn't fit over the rotor.

If there's a way to make my S4 rotors work, I'm all for it. But in looking at the positioning of everything, if the 993 rotors have less offset (the hat isn't as deep), then that sounds like what I'm looking for.

ROG100

You need the 993 rotors as per Tims post.
$112.95 each

LT Texan

I don't want to add misinformation, but I thought the 993 turbo 2 piece rotors were required:
993 351 045 10 / 993 351 046 10

ROG100

Dan,
You need those if you are fitting "GTS Big Red/Black" calipers.
Roger

928nut

Adam,

tell me I'm wrong ! Is that aluminum ball joint I see in your first picture ?

Jan

atb

So here's a pic of the rotors side by side. The S4 is on the left and the 993 is on the right. You can see that additional offset of the S4.



The rotor still sits just slightly inboard, but not enough to interfere with anything. The inboard brake pad is a tight fit compared to the outboard pad, but a couple miles on it and it won't matter.



Here we go, finally, S4 calipers with adapters (thanks Roger!) on an OB with 993 front rotors:

atb

Hi Jan,

Hey thanks for keeping a head up for me, but those are steel. Courtesy of fellow Pac NW'r John Davis.

mark kibort

Hey, you know Im into these upgrade mods, so something comes to mind. Does this mean that you can use the 993turbo rotors and use an adapter bracket that just moves the caliper outward and allows for the S4 calipers to be mounted to the OB's stock assembly???

good news for scot, in that he could get bigger rotors and the S4 calipers for only the cost of the new rotors, adapters and calipers. true??

Fabio421

Yes, thats the idea. I have made these adapters. I will be test fitting them in the next day or so. S4 calipers with 993tt rotors. PM me if you want to try a set.