Merrill Genuine Y-40 Valve Body With Brass Insert Free Shippinggenuine Merrill Y 40 metal valve body with insert. For Merrill Y1 and Y2 Yard Hydrants. This is the piece that connects the Y1, and Y2 hydrants to the plumbing. The end of the valve body that threads onto the hydrant has an inner diameter of approximately 1 inch, and an outer diameter of 1 3 4 inches. The end that threads onto the plumbing has an inner diameter of roughly 1 1 4 inches, and an outer diameter of about 2 inches.