Master Power Brakes sent us one of their Brake System Diagnostic Kits, and rather than just run it in our new products section, we figured it'd be neat to actually put it through its paces on one of our rides. My '46 roadster pickup was the obvious choice, especially as I've not been 100 percent happy with the brake system since getting the truck on the road. While the front and rear brakes are stock Caprice, albeit rebuilt with new calipers, wheel cylinders, hoses, pads, and shoes, and the combination valve is also from a Caprice, the dual circuit master cylinder and booster were aftermarket items more commonly used on lighter hot rods. I didn't know the cylinder bore size and had a feeling the 7-inch booster was too small, but I'd selected it as a 9-inch version would have been too large to fit between the steering column and the inner fender panel. It should also be noted here that the brake pedal is the Caprice item, albeit modified to allow it to mount in a comfortable position, yet offset the pushrod two inches to the left to align with the booster on the firewall, though the ratio remained unchanged.

The brakes had never felt "right" and it took considerable effort to bring the truck to a halt after the first, and easy, initial use of the pedal. All things considered then, the system needed inspection, so I put it up on the rack at the Source Interlink Tech Center and unboxed the diagnostic kit.