Turned out the floorboard itself was stopping the brake peddle from going all the way down. Check out part 2 of the brake system troublshooting guide that defines brake parts and help you figure out what your hot rod needs.

Five Common Brake Problems In Cars Axleaddict
Street rod brake problems. In august of 2018 harley davidson emitted a massive global wide recall for faulty brakes on close to a quarter of a million units of some of its. Crawl under the care and watch the peddle action while someone else steps on the brake peddle to see if you have enough floor board clearance. The original jaguar disc brakes arent the greatest looking or operating units so most rod builders equip the differentials with wilwood disc brakes. Pump the brake and hold it for 30 seconds. Doing that feet up challenge thing at stop. Rod and custom magazine.
Kinderman wants to use hydroboost brake system on his 1940 ford street rod. Perhaps reflecting its price tag the street rods brakes are a little offon. Shipping of new units has also been put on hold. Hook up the front calipers leaving the plug in the master where the backs hook in. In most master cylinders it is necessary to have the fluid level approximately ½ from the top. I have built my own street rod and had the same problem.
Do you have a hard pedal. We see a lot of brake drag problems caused by a master cylinder that is too full of fluid. Wont crutch other brake system problems wrong master cylinder wrong pedal ratio. I found it difficult to be nuanced especially with the rear brake. If the system is overfull there may not be enough room in the reservoirs for the fluid to return. Pedal ratio refers to the relationship between the pedals pivot points and the length of the brake pedal.
If yes reconnect the rear brakes and pump and hold the brake for 30 seconds. However pedal ratio can be as big a problem in either case so it must be considered as a potential cause for a hard brake pedal. Jaguar rear suspension systems are being used in street rods even though they are getting more difficult to find. If no then the front calipers are at fault.