When I started looking for Aluminium front brake callipers, I thoughts it was going to be fairly straight forward and get something relatively quickly off-the-shelf so to speak. Not so!. I need better brakes as my legs are not as stronge as they were.
Firstly, I'm using (or they have been on the car for 30 yrs) Rover SD1 struts, the brakes are solid discs and 2-pot callipers. I own a set of NOS genuine Rover 4-pot callipers and vented discs but never fitted as I calculated that the clamping force of the 4-pot and larger pad was only a few % better than the original and not worth the effort.
So went to SD1 owners web site, and there was nothing! except if you want to fit 17-19" wheels, and I'm sticking with my 15" wheels.
Looked at a Face-ache site for Modified SD1 and some have used a mod done 30 odd yrs ago using a jag XJ12 4-pot and vented disc, the calliper have pistons of 48mm dia compared with the SD1 of only 41mm dia which results in a 37% more clamping force and larger discs giving 10% extra leverage. Win Win Result I thought, no not really, as you have to have a special collar/adaptor (which no one makes any more) for the discs to bolt to the SD1 hubs and the calipers have to have either 2 slots drilled/milled in the calliper lugs to fit, which makes them useless if you need them to be overhauled in the future as most companies do it on an exchange for old unit basis (as they will be condemned as unusable! due to the lug holes being "damaged"). Also the callipers weigh a hefty 7.8kg!!.
I looked at Wilwood and found the perfect ( or so I thought) calliper. Aluminium (tick), 4-pot (tick), 48mm piston dia (tick), for disc width 22-24mm (tick), up to 300mm disc dia (tick), radial mounted (tick), Dust seals NO (au bugger), and do Wilwood do one WITH dust seals , no. As I will be using the car on the roads mostly (will avoid the wet) I think dust seals are important, unless someone here can advise otherewise.
I did contact a manufacturer who offered a replacement Ali 4-pot calliper for the Jag XJ12 and when I asked for the piston dia he said it was 41mm and they don-t do 48mm (in my books that's a retro grade step as you have lost 37% clamping force), this does not inspire me with confidence in their products as surely it should be like-for-like at the very least.
So can you guys throw me some names of uk (to start off with) aluminium calliper manufacturers who make 4-pots, I-ve tried a few but no luck for either Rover SD1 or big Jags, you might just come-up with a name I-ve not found on the interweb.