Brakes

Hi Dennis

Some light reading for you! I agree finding rear calipers with large enough pistons and a built in handbrake is a real challenge. To maximise your choice of calipers with the right size pistons I suggest you fit the Wilwood MC4 Handbrake Caliper alongside  you choice of hydraulic rear caliper which will probably be 4 piston. The Willwood Calipers are a good choice being light strong and relatively cheap. The supplier I used for my Hi-Spec mounts no longer makes them. Speedy cables can make you a handbrake cable to the design you request. I run 15 inch Azev A wheels with my R132 -6 Hi Spec front Calipers and B4 Hi Spec rear calipers on Fiat Coupe/Integrale discs. The Wilwood calipers are better quality and very good value.  

Feel free to ask when you have read what I have supplied you. NB the 2018 Word Document first and yes I know I never finished the edit.

Rally Design sell the Wilwood Midilite 4 piston caliper at good value which is what I would recommend to you to build mounts for using the 284 x 22 vented discs from a Fiat Coupe/Integrale all round. Probably 38.10 front pistons and 31.80 rear pistons with the standard MC which give a 58% front balance. This caliper is light strong and easy to get mounts made for in alloy as it is a radial mount. If you needed more braking (unlikely) you would add a twin servo available from Car Builder solutions. Pads that work well at low temperature i.e. road spec recommended.

https://www.rallydesign.co.uk/product_info.php?cPath=562_588&products_id=8317

I have attached a filled out calculator with standard S2 vs different Wilwood piston sizes on 284 discs. I would not want to go beyond 57mm on the pedal travel and that assumes you have sorted out the play in all standard S2 pedal box push rods.