Phillips head screw for trailer hub cap

[dawsonr]

After 10 years of my American trailer sitting in my back yard, I had to move it. In doing so, I snapped a valve stem off on a wheel. Tryin to remove the screw that holds the hub cap on the wheel, I stripped the Phillip's head. The only way to get at the screw out was to drill it out. So, now I need to replace the screw. Anyone know where I can get a new one (see photo)?