Brake Bias Valves

Aim and Objectives

Aim:•The aim of the lesson is to recognise the need for brake bias (proportioning valves) within a vehicle braking system

Objectives:By the end of this session you should be able to:

•Identify the location of a brake bias valve•Explain how a brake bias valve operates•Evaluate its performance on the vehicles braking system

Can be located in two areas:

•Within the engine bay, close to the master cylinder•Within the driver area (this is common within race cars)

Where is it located ?

• The driver/engineer can adjust the brake ratio between the front and rear brakes

• This critical to the stability of a vehicle during the braking and steering; too much rear brakes will tend to cause the car to spin; too much front and the car will not turn.

• In the diagram on the left, the pivot/adjuster can be altered to switch how much braking force can be put to the front and rear.

• Engineers will set this ratio up depending on the type of work the vehicle will be doing (Indy 500/drag etc.)

What does it do?

Schematic of a Brake Bias valve

Research Exercise

In pairs, discuss the set up of a brake bias valve for the following types of motor sport, explain if you would have more bias to the front or rear brakes.

•Drag•Rally•F1•Indy 500

•Use ICT to research the sport, and report back to the class your suggestion.

Summary

By the end of this session you should be able to:

•Identify the location of a brake bias valve•Explain how a brake bias valve operates•Evaluate its performance on the vehicles braking system