Apparatus and method for calibrating float valve

A method for calibrating a spring-balanced float in a vent valve for a vehicle fuel tank, comprising the following steps:

• providing the vent valve with an axially adjustable spring support in a lower portion of the valve below the float for supporting the lower end of the spring acting on the float, the axially-adjustable spring support further including an aperture designed to admit force measuring means to be inserted against the float;
• inserting force measuring means through the aperture to move the float to a desired position, and measuring the downward force of the float as balanced by the spring while the spring is seated on the axially-adjustable spring support in a first calibration position;
• adjusting the axially-adjustable spring support as needed while the float is at the desired position until the downward force of the float as measured by the force measuring means meets a predetermined calibration standard, thereby defining a second calibration position;
• and
• securing the spring support to the vent valve in the second calibration position.