Ignoramus7928 wrote:

....
This is an old belt. Could it lengthen due to time etc? Would
replacing it with a new belt make any sense?

The belts I thought would fit, are of wrong size unfortunately. Are
they available at auto stores?

I need something like 1/2" by 36" V belt.

Yes, belts stretch (and, having stretched glaze) w/ time...

The owner's manual will provide the correct size (both cross section and
length) although unless the present ones are badly deteriorated you
should be able to read the size code off the belt. Any decent-sized
auto supply should be able to match it, assuming it isn't some special
cross section...