randomhick35

I have landed myself in a bit of a situation. i am in the process of rebuilding the brake system on a 66 911 and am in need of help. I just purchased 2 new brembo vented front rotors from porsche parts direct [http://www.porsche-parts-direct.com/epc-items.asp]. the problem is that by a micrometer these are about .8051" thick, whereas the origonal rotors are .416" thick. admittedly the fronts have been pretty worn, but even new they cant be more than .45 or .47" thick. my problem is that i cleverly have my calipers out being rebuilt so i cant check to see if these rotors will fit or not. Common sense tells me that these rotors are almost twice as thick so there is no way that they could fit in the same caliper, yet i have found three different sites that all sell the same vented rotors for 65-67 porsche 911. Has anyone done this before? does anyone know how wide the calipers can go with the pistons maximally pressed in? any help is appreciated

randomhick35

I am also having a hell of a time seperating the rotors from the hubs. there are five bolts holding them together, but after removing them, it seems they are just press fitted together, but i still can't manage to seperate them, even with a crowbar. I dont care about the rotors but dont want to damage the hubs. any advice? anyway here are the pictures of the new and old rotors.
in one picture, the two rotors are just sitting on top of each other to give you an idea of the thickness

Steve Weiner-Rennsport Systems

Well Sir,.......clearly you have the wrong rotors for your car. Those early 911's had solid rotors and the "S" cars had the vented ones with wider calipers to suit.

Two choices: procure the right rotors for your '66 911 or update the brakes with the vented rotors and some M front calipers. You can use the M rear calipers from any '69-83 911.

The rotors are not pressed to the hats; they are likely simply corroded together due to being dissimilar metals. Soak them overnight with an effective penetrant spray such as Wurth's Rost-Off, Zep Corrosion buster, Kroil,....etc. and that should do the trick after a quick whack with a hammer on the rotor surfaces. Clean everything up on the hub before you mount the new rotors and pay careful attention to torque values and the order you do them.

randomhick35

i know that the origonals are solid. based on the fact that three seperate sites sell the same vented rotors for a 65-73 911, my belief is that these are aftermarket pieces designed for my car, but without the calipers, i can't confirm this. I find it hard to believe that three independant seperate sites could make the same mistake, but it is possible. Is there anyone who can tell me the maximum width of the caliper with the pistons fully depressed? i also solved the hub problem, just used a bigger crowbar.

Peter Zimmermann

The correct rotors for your car are not vented, the vented rotor first appeared on 911S models. The alternative is to find later model "M" calipers with the wide opening that will accomodate vented rotors, or original early calipers that use the 7.3 mm thick spacers between the inner and outer sections of each front caliper (your calipers will not have the spacers, instead will have a single seam where the two halves meet). If you change the car to vented parts be sure to do a part number search regarding hubs. All the front wheel bearings are the same, but I seem to remember something about hub thickness changing at one point.
Pete

randomhick35

thanks all, does anyone have a thought on adding spacers to my current calipers?