Vented Rear Brake Rotor Combinations for a 1990 Coupe Quattro by 90quattrocoupe

6 minute read

Vented Rear Brake Rotor Combinations for a 1990 Coupe Quattro

Compliments of 90quattrocoupe @ http://forums.fourtitude.com

Below you will see two possible ideas for rear vented rotors. I tried a couple of different calipers and rotors, basically running with ideas I got from other original thinkers on other forums.These are a couple of different combinations using two different rotors, two different calipers, both off the same carrier. The rotors are both 280X22mm. The g60 rotor weighs 11lbs and the New Beetle weighs 13 lbs. It is now 2010. Another option is a B6 S4 rear rotor. It is 300X22, but you can have it turned down to 280, and use the shims the same as the New Beetle rotor.

These are the two rotors I used. CorradoG60 and a New Beetle. For the peoples in the old countries, all the G60 rotors should be the same as the Corrado. This was the only G60 imported to the states. The New Beetle rotor is the same as the A3, which we haven't gotten either.

Both rotors have had the center bore increased from 65mm to 68mm. The G60 rotor was redrilled from 4X100 to 5X112. The NewBeetle/A3 was slotted from 5X100 to 5X112.

I used the Corrado for the setup pictures. This is the aluminum A8 caliper on an S8 Carrier. This allows for the 280X22 vs the 269X22 on the normal A8. This caliper weighs slightly over 3lbs.

I got this idea from Stick Insect(David) on the S2forum. He mentioned using an easier to find caliper than the A8. I happened to have an S6 Rear caliper lying around, and fit it up to the S8 carrier. It fits just like the A8. It may be easier to use the parking brake cable on the this caliper as it is in the same place as the coupe rear. The A8 caliper has the parking brake mechanism in a slightly different location, but it stills pulls from the side and not the front. The S6 caliper weighs in at 6 lbs, but is definitely more available from a wrecker than the A8 caliper is.

This is the G60 rotor with just the S8 carrier.

As you can see from this picture, the G60 rotor comes a little close to the inboard edge of the carrier. It was even closer before I took the next step.

I took a look at the carrier and noticed that they had excess material on the inboard edge from the bolt on area. The least amount of excess material was 1.5mm. So I had an additional 1.3mm milled off each of the carriers. This allowed breathing room for the G60 rotor.

This picture shows the gap between the S8 carrier and the bolted up A3/New Beetle rotor. It is more centered, but as others did on this forum, you need to use 2mm spacers when bolting up the S8 brake carrier to the rear hub carrier. This moves the carrier outboard.

Now the brake carrier is bolted to the outside of the hub carrier, and not the inside like the coupe. Luckily for us the brake carrier is machined on both side of the mounting holes, just as the hub carrier is.

I am going to use the G60 rotor with the A8 carrier, and when they wear out, I will use the New Beetle rotor.

Remember, if you end up trying one of these combinations, the A8 caliper or the S6 caliper, they are used on the opposite side of the car, from where they were normally used. The right caliper goes on the left side of the Coupe and the left caliper goes on the right side of the coupe.

As an update to that thread, the B6 S4 rotor, which is 300X22 has the same offset as the New Beetle rotor. So instead of having the bolt holes redrilled and the center hole rebored, all you have to do is have the rotor turned down from 300 to 280 and you are set. Paul(S2central.net) on the S2forum just recently did this, and it came out great.

One thing about using hubcarrier and hubs from a Euro coupe on a states coupe. You have to watch what year you get them from. Up to 1992, the struts and carriers used 12mm bolts. After 1992, the hubcarriers bolted to the struts using 14mm bolts. I did not realize this until I received the hubcarriers from the UK. The ones I bought came off a 95' coupe, and were 14mm. I thought I was screwed, but being a backyard mechanic from way back, I just reamed out the strut holes to 14.3mm. The center lines were the same, just the holes were larger on the hubcarriers. 

I used these to ream them out:

There are available from McMasterCarr.

Greg