Besson 3V Compensating Valve Springs

[Aychelby]

I was cleaning my old Besson 3V compensating tuba (I think its a 1968 223) and noticed the 3rd valve spring was smaller than the other two. Anyone know if this is right, or did that spring maybe get incorrectly replaced at some point? I know on 3+1 compensating horns, the 4th valve spring is smaller because that valve is typically physically smaller, but at least on this horn, the 3rd valve is the same size as the other two.

The 3rd spring is roughly 5/16" in diameter by 2 3/16" long while the other two springs are 7/16" in diameter by 2 1/2" long.

[highpitch]

A whole new set is not expensive, I'd just replace them.

eBay has them by the droves, under $20.