Once we completed the changeover on the front brakes, we felt the pretty steel braided brake lines that were installed throughout the Speedster were not large enough to accommodate the other changes we made to the brake system. The F-1 wheel cylinders were plumbed for 7/16-20 thread, as the originals were but the steel-braided lines were attached to the cylinder via banjo bolts. The braided lines themselves were only about 1/8-inch diameter before terminating in a female AN fitting that the banjo screwed into. Because the stock brake lines in 1934 and 1948 should be at least 3/16-inch diameter, and we added a larger remote-fill reservoir to our Wilwood master cylinder, we decided to re-plumb the whole car with poly-coated steel tubing and remove the stainless altogether.
We started with selecting some suitable brake hoses. Both front hoses and one of the rears had to be:
A. 20-inches long
B. have 7/16-20 male threads on one end for the wheel cylinder
C. have 3/8-24 female thread on the other end as well as a 5/8-18 external thread for the frame mounting tabs. The 3/8-24 thread accepts a standard 3/16-inch inverted flare male nut found on most pre-made brake lines.
Rummaging through our brake hose buyer’s guides, we came up with BH33511 for the 20-inch hoses and BH38316 for the right rear hose which needed to be 25 inches but did not need a bulkhead thread on the outside. We also chose a BH36753 hose to transition from the steel line to a flexible distribution tee on the rear end. This hose had a brass tee junction on one end of it for the two rear steel lines and a bolt hole to mount it to the pumpkin.
Once we installed our brake hoses, we started bending pre-made poly-coated brake tubing to fit the chassis. We joined the front brakes at a tee just in front of the driver’s side motor mount (Weatherhead # 7812) and back to the Wilwood master cylinder from there.
For the rear, we decided to add an adjustable brake valve from Inline Tube that was mounted to the floorboard with the adjustment knob reaching through the floorboard where the driver could adjust it on the fly. We left it all the way open so we still had 50/50 brake distribution, but this could be adjusted by the driver as the rear of the car lightens as the fuel load lessens or it could also be used to shut off the rear brakes entirely if there was a hydraulic failure. The Speedster is very light, and the new brakes we put up front should be enough to stop the entire vehicle if necessary.