Anyone ever had a sender float that perhaps developed a leak?

My gauge is typically 15-25% off. When I refuel, It never quite hits F. By the time I've done 75miles, it's either at or just below 3/4. I've cleaned and repaired the sender twice, I have no shorts in my cluster grounds... boy would I love to figure this one out.

__________________
1981 240D 4sp manual. Ivory White.