SWB Brake Confusion

[Adelaide901]

Hi Gurus,

A quick question about early 911 brake discs/rotors.

Looking through the options on Pelican there are front discs that are for years 65 - 68 and front discs that are for years 67 - 69. Given the overlap is there actually any difference? For example if they both equally fit a 68, then would they both equally fit a 65?

Im confuddled??

[304065]

64-68 NORMAL discs are not vented

67S, 68S and 69- T E S are vented

[djpateman]

Solid rotors were also used on the 912. I have a feeling that some 1969 T and perhaps later T's may also have had solid rotors. Anyway, the hubs are different for solid and vented rotors. So, for a complete solution going from solid to vented brakes requires hubs, rotors and calipers on the front suspension.

[Shoepop]

Originally Posted by 304065

64-68 NORMAL discs are not vented

67S, 68S and 69- T E S are vented

Add 68L to the vented list.

[Adelaide901]

djpateman - you just saved me a bundle. I was going to buy the vented rotors (thinking cooling) for my unvented rotor hubs, calipers etc. Thanks!

[djpateman]

Vented rotors will improve cooling quite a bit. I am working on just such a project for a friend with a 66. You can space out your front calipers to work, but the spacers and bolts have to come from the correct caliper anyway; and they are plentiful enough.
My project will use an aluminum Brembo caliper that was found with 3" bolt spacing, 48mm pistons and pads about the same as the aluminum S caliper; thus fully equivalent to the S caliper but with 3" spacing to fit on the original struts.
For the rear, I need to get special calipers from the UK and 944 rotors; these have 40mm pistons that are bigger than the 35mm unvented caliper or 38mm vented caliper that would have been on or available back in 1967. The rear vented caliper for the 67 S is nearly unavailable at any price, and the original rotors much the same situation.
All in all, going to vented brakes is a very good solution since it improves thermal capacity, and cooling with only a small weight penalty (and inertia penalty). The trouble is that the calipers need to be widened with spacers (in general, or made for the width required). To correct the rotor offset on the front requires different hubs.

Yes it is a bundle, but after experiencing brake fade it seems a small price to pay for peace of mind. For this type of project one needs a plan and a budget.

[ttweed]

Originally Posted by djpateman

The rear vented caliper for the 67 S is nearly unavailable at any price, and the original rotors much the same situation.

The original rear vented rotors for the '67-68 911S were still available from the factory the last time I checked, but they were nearly $500USD apiece. An early 944 vented rotor can be modified fairly easily to fit, though, and is cheap.

Yes it is a bundle, but after experiencing brake fade it seems a small price to pay for peace of mind. For this type of project one needs a plan and a budget.

Undoubtedly, but adding calipers that have more clamping power to the same size vented rotor will not increase the thermal capacity of your brake system. Using fresh high-temp fluid and pads and adding cooling vents with ducting to the brakes to force-feed fresh air to the calipers and rotors is the best way to prevent fade, if you aren't going to increase the mass of the rotors.

BTDT,
TT