I recently learned that there is a spring in the latch to keep it closed when on the fastening loop. Who knew? The springs in the latches on my 1966 belts weren't working and the latch could not be relied upon to stay fastened.
It took just a few minutes to remove the belts (5/8" wrench for the lower bolts and big ass Phillips for the upper). After drilling out the rivets I found the remains of the original springs. I purchased a couple of so-called "clothes pin fasteners" made of spring steel. Using a side cutter I trimmed them to act as return springs. After installing the new 3/16"x 3/8" rivets, all was well. If the upper bolt has been mistreated a replacement is 7/16"x20.
While the belts were loose I soaked them in hot water and Simple Green. Today, they're a different color. 0000 steel wool got the metal shining again.
This is a simple fix that cost about 1.50 in parts and two hours of time.
Bob
66S