SD1 front brakes fit a P6B?


Staff member
Mine are Fosseway four pot calipers and vented discs. Rears are XJS Jag.

I have seen others used, but are mainly Land Rover (IIRC?) and modified transit discs. Also, there was someone making up distance pieces so you could use the P6B front calipers with vented discs but I don't think these would stop better, just be better against brake fade.



Well-Known Member
My solution was a pair of Outlaw racing alloy 4 piston calipers from the States and redrilled pcd vented and grooved discs from Vauxhall Omega. Calipers bolt straight on but I needed spacers to get the disc centred. They come with stainless pistons as standard and
are super lightweight.
Wilwood do very similar offerings.
The calipers were around £100 won on eBay, discs won for 99p o_O machining work £30, pads around £50.
All still untested but they have the makings of a strong setup
Pad choice goes a long way to improving the stock set up.

FYI some data I have saved.

Caliper piston areas​

Austin Princess

Pistons 38 mm x 4 = 3.142 x 19 x 19 x 4 = 4537 sq mm.

Rover V8 caliper

large piston 57 mm = 2,552 sq mm

small piston 40 mm = 1,256 sq mm x 2 = 2,513 sq mm

Total piston area = 5,065 sq mm

Rover pad = 4056 sq mm

Fosseway caliper for Rover

Pistons 41 mm x 4 = 5281 sq mm

Fosseway pad = 89 x 51 mm = 4,539 sq mm

Note single pot slider calipers are calculated as 2-pot, so the Escort RS Turbo Series 2 with 60 mm pistons has a total piston area 3.142x30x30x2= 5655 sq mm.


Well-Known Member
Handbrake calipers are slightly different though aren’t they? Although very similar looking to the P6 Dunlop ones..

Pistons in my Outlaws are 1.75” and 1.62”/ 44.45mm and 41.14mm, so 5759 mm2. I can’t remember off hand what size the Hawk pads are