Dual chamber master cylinder for drum brakes

[KULTULZ]

Function and Purpose of the Proportioning Valve

The proportioning valve typically connects the master cylinder to the rest of the braking system, but sometimes it is independent of the cylinder. This valve is necessary for optimizing front-to-rear bias, also referred to as brake balance. It is a spring-loaded component that activates when fluid pressure builds when you step on the brake pedal. Then, the valve’s plunger unseats and fluid rushes into the calibrated range. Once this happens, the spring gets compressed and the plunger blocks the fluid from passing through. Even pressure distribution among the front and rear of your vehicle is important for safe and reliable braking performance.

Signs of a Failing Proportioning Valve -

Just like any other part of your car, the proportioning valve may eventually fail. There are a few different ways to tell this is happening. First, you might notice your car is taking a nose dive when you suddenly apply the brakes. Then your car may not stop fast enough. If your rear wheels lock up easily, especially when you drive on wet surfaces, it is a good sign your proportioning valve is going bad. You can also read about more signs your braking system isn’t functioning properly.

Causes of Valve Failure

If you sense your valve is failing or not operating properly, you might be wondering how this happened. Sometimes proportioning valves simply fail after a long time of driving. Other times, you might have caused the problem by making a modification that impacts your brake balance. Here are some modifications that can influence your front-to-rear bias.

Modifications that can increase front bias:

• Increased diameters of front caliper pistons
• Increased friction of front pad coefficient
• Increased diameter of front rotor
• Decreased diameters of rear caliper pistons
• Decreased friction of rear pad coefficient
• Decreased diameter of rear rotor
• Less sticky tires
• Less weight on the front axle
• A loaded rear axle
• Lowered vehicle causing a lower center of gravity

Modifications that can increase rear bias:

• Increased diameters of rear caliper pistons
• Increased friction of rear pad coefficient
• Increased diameter of rear rotor
• Decreased diameters of front caliper pistons
• Decreased friction of front pad coefficient
• Decreased diameter of front rotor
• More sticky tires
• More weight on the front axle
• An unloaded rear axle
• Raised vehicle causing a higher center of gravity

SOURCE - https://www.sundevilauto.com/what-do...for-my-brakes/