Brake System Diagram - Street Rod

This diagram shows a typical street rod brake system. A 2 PSI residual pressure valve (RPV) is needed in the disc brake circuit, and a 10 PSI RPV is required in the drum brake circuit as well as an adjustable proportioning valve (APV).

This diagram illustrates the 2 most common types of fittings used in street rod brake systems. The first is the inverted flare type, which is used by most domestic production cars and trucks, and on the bottom is the -3 AN (which is pronounced as dash three A N or number three A N). The inverted flare system uses a 45° double flare to seal, which is tubing that is folded over into itself before flaring outward. The most common size of tubing used is 13/16" O.D. and utilizes a male fitting threaded 3/8" - 24.

The -3 AN also makes use of 3/16” O.D. tubing, but it is not folded into itself. Rather, a female coupler (threaded 3/8"- 24 internally) is slipped onto the tubing, then a reinforcing sleeve, and then the tubing is flared into a 37° angle.

Due to the opposing flare styles and angles, the two systems will not seal to each other unless an adapter is used. Because we have no idea which fittings system you intend to use on your car we provide the residual pressure valves, adjustable proportioning valves, pressure brake light switches and thru-frame fittings with neutral 1/8"- 27 NPT (national pipe tapered) ports. To attach your chosen style of brake lines, simply order the 1/8" NPT adapters that correspond to your brake line fittings.

Obviously, the more adapters, splices, and fittings a given system has, the greater the chance for leaks and the more expensive it will be. With that in mind, you need to choose which system you intend to use (AN or inverted flare) and use it throughout, with the least number of splices and fittings possible.