Need correct Brakes for BT21C

I can't believe there is snow in my forecast! Garage is COLD but I'm still moving forward on my BT21C restoration. I've found two sources for the front hubs and rotor replacements so the brakes are next. Presently I have steel Girling 14LF (FF) calipers front and rear with 5/8” Girling Master cylinders. The calipers must be replaced and I believe the Master cylinders must also be replaced. The clutch master cylinder is .7”.



In the boxes of parts that came with the car I have a pair of Lockheed CP-2094 alloy calipers and a pair of Girling D12R (I think) alloy calipers. Both calipers have 1.7” pistons. Both calipers have 3.5” mounting hole centers. The Girlings are mounted with 7/16” bolts while the Lockheeds use 3/8” bolts. The dimension from the mounting plane to the center of the rotor is similar for both calipers at about 1”. I have the original MRD front caliper brackets and they have 7/16” threads with heli-coils installed. Are heli-coils normal? I'm wondering if the threads were originally 3/8” for the Lockheeds.


My original factory documents say the F2 version came with Lockheed calipers and Formula Libre (FB) had Girlings. I wonder if I have a hybrid of sorts. Photos of Al Murray's car shows Girling AR calipers on the front and Girlings on the rear. The article also says he has 3/4” Master cylinder for the front and .7” for the rear.



Right now I am looking for recommendations as to what I should have for master cylinders and front and rear calipers and piston sizes.

Need to remember it became just another used, old race car for a time and people didn't worry about having all the original bits and pieces. never mind making modifications to try and keep it competitive past it's best days. The BT8 I ran for so many years had been modified noticeably over time by it's original owner to keep it competitive.

Unless you have a history of owners you can contact to ask them what was done when they owned it, best advice is to pick a configuration and go with it.

I ended up purchasing a pair of AR2 calipers with 2.0" pistons on the front and will use the D12R calipers that came with the spares. I also purchased a Girling .75" master cylinder for the front and a Girling .7" master for the rear.

The unused AP Lockeed calipers and the Girling 14LF calipers available so make an offer if you want them.