There are many different valves used in the conversion from drum brakes to disc brakes and in brake systems in general. Have you ever wondered about the various types of valves that make up your brake system and what they do? This post offers a description of what some of those valves are and how they relate to your vehicle and situation.
For your disc / drum brake system, a metering valve is essential for proper balance. A metering valve will control fluid flow from the master cylinder causing the rear drum brakes to engage just before the front disc brakes. This allows the car to settle evenly under braking instead of nose diving.
Residual valves are used to maintain constant pressure on the brake system. For drum brakes, a 10 lb. residual valve is used to hold pressure against the springs in the drum. This allows the drum brake to engage more quickly and reduces pedal travel. For an under-the-floor master cylinder brake system, a 2 lb. residual valve is used for disc brakes to keep brake fluid from flowing back down into the master cylinder.
A combination valve provides everything you need to balance your brake system in one compact unit. Combination valves include a metering valve for disc / drum systems and a proportioning valve plus a pressure differential switch. We also have combination valves for disc / disc systems without the metering valve. The proportioning valve modulates pressure to the rear brakes so that as weight is transferred to the front wheels under heavy braking loads and pressure on the system is increasing, less and less pressure is being applied to the rear brakes. This minimizes rear wheels lockup as weight is reduced on the rear axle. The pressure differential switch is a safety feature that can block fluid flow to either end of the car if a component becomes damaged and is leaking fluid. This allows you to maintain pressure to part of the brake system at all times.
Adjustable Proportioning Valve
An adjustable proportioning valve is used to set rear brake pressure reducing rear wheel lockup. This valve allows rear brake pressure to be reduced for driver preference. Adjustable proportioning valves are typically used in conjunction with a metering valve.
Contact the Street Rod, Classic Car and Muscle Car Brake Specialists
Are you looking for a new valve for your brake system or have questions about your brakes in general? Your classic car deserves better than salvage yard brake parts or the original components included with your ride, and we are here to help. For technical assistance, pricing information, or to place an order, contact the braking pros at Master Power Brakes for more information!