I agree with Graham. They work well but add additional clutter. Be sure to use a balanced handbrake, one with a single cable running to both calipers as it will make adjustment much easier as the cable stretches.
Hand brakes *may* need to be mechanical. Or at least on a separate system from the main brake systems incase of failure. (Not exactly sure which one it is though...)
Wilwood does make a mechanical spot caliper. So does brembo. A separate hand brake caliper will free up options for the main rear caliper, especially if you go with Wilwood, AP, Brembo, etc. fixed calipers.
My mistake for not looking closer. I have mechanical calipers. I've heard of folks using a hydraulic line lock as an e-brake but it doesn't seem particulary safe. This isn't much different than using something like these. I'd suggest looking at the mechanical units as an alternative.
Willwood and Ford both have a very neat parking brake setup. They have a small cable opperated drum brake inside the hat of the brake rotor. The Ford setup is from the Explorer and will fit the explorer 8.8" rear end and some 9" rear ends. I think the willwood may be more generic.
I don't know if either of those could be adapted to the GT40 uprights, but they do get rid of the ugly parking brake caliper and they will let you run a race style caliper that does not have an integrated parking brake.
My Ford Explorer handbrake is totally useless and could never be classed as an emergency handbrake. The only thing it's good for is to stop the coffee cups falling over in the centre area behind the shift lever.
The shop that is doing my brake work is looking into the brake drum in the hat wilwood setup. It is going to be a buget thing for me but I will do my GTD that way if at all possible.
By the way this particular shop was a Superperformance Corbra dealer in the past and does VERY professional work on a lot of race cars as well as expensive steet stuff. Anyway he will not install the wilwood mech. spot parking brakes on cars anymore. The problem is that they will work on slighly sloped ground but sooner or later the owner will put the car on a grade that the calpier will not handle and he has had more than one car roll down the hill into someone else.
He said they are a go cart brake and were never ment to be used on a car. FWIW
Lastly I am not sure if they can be opened up to take a thick rotor like 1 1/4" or so.
You are in SF, I'm sure that you know about parking on hills.
You should always park with the car in gear. If you do that you won't roll away unless your clutch fails also. You are also suposed to turn your wheels in to the curb and let your car roll untill the wheel hits. If you follow those two rules it would take an act of god or a car accident to move your car down the hill.
I don't even use my parking brake because it's pedal style and it just gets in the way.
There are some people that put them on at stoplights, drive with them engaged, or use them for "drifting". I think those three are the only ways to wear out a parking brake before the car is ready for the scrap heap.
Liability is probably the only reason they stopped using that calliper. They know that there are a lot of people who lack common sense (especialy in SF). They don't want to pay the price for someone elses stupidity.
Please let us know how those willwood drums turn out. I have been thinking about using them but I need a 12" rotor and I would like to use a 2 piston Brembo caliper to match my front brakes.
Thanks for all the replies chaps, Altho I perhaps should have made my intenetions clearer. In the UK, the parking/hand/emergencey brake has to be 'mechanically' operated to pass an MOT & be road legal.
Line locks, hydraulic handbrakes etc are not strictly legal.
I've fitted Ap500 4 pot calipers to the rear & they do not have any mechanical brake facility.
Graham & Neal, thanks for your feedback. I had heard varying reports on the wilwood 'spot' caliper & I really appreciate your opinions. I'll order some up & give them a try.
AP certainly did do a handbrake cable operated caliper. I have a pair sitting on the shelf for future use. However I think they are no longer available and what I bought was old old stock from Roy Lane at Tech Craft.
Never rely on a hydraulic hand brake to hold you car parked for any period of time especially if your brakes have recently been warm/hot. As the rotors/discs cool they shrink loosening the grip of the hand brake. On more than one occaidion I have heard of hydraulic hand brakes failing in this regards with cars rolling away!
IMHO never use the hand brake on your 40 whatever type you have. Always leave in gear with the handbrake off. With typical long periods of inactivity often after a blast on quiet roads or track use, you may get some sticking of pads to rotors/discs. I don't even use the handbrake on my road cars either, but just leave in park or in gear.