This invention is directed to a method for inhibiting particulate material in a pneumatic tire from adversely affecting operation of a tire valve assembly The method involves inserting a filter element into a valve stem passage of the valve assembly while the valve assembly is connected to the wheel assembly, and then installing a sealing valve in the valve stem passage. The invention also relates to a tool for inserting the filter element into the valve assembly to inhibit particulate material from passing into the valve assembly while allowing fluid to pass therethrough. The tool comprises a body selectively attachable to the valve assembly. The body has a plurality of passages therein, including a plunger passage, a filter passage and a fluid passage, and a selector valve having two bores therein for selective registry with the plurality of passages. The selector valve is movable between a first position in which the fluid passage is in fluid communication with the valve stem passage and a filter element is loaded into one of the bores in the selector valve through the filter passage, and a second position in which the fluid passage is blocked against fluid communication with the valve stem passage and a plunger is adapted to move through the plunger passage and the bore loaded with the filter element to push the filter element into the valve stem passage.