Drum brake springs

[68haywagon]

Hello again to everyone.
I'm doing a brake job on my 68 and replacing shoes, hoses, spring and adjuster kits, and the wheel cylinders. When I went to the front I noticed the left front drum had a crack in it. I went to AZ and purchased 2 new drums for the front. The old drums have a spring that wraps around the outside of it. I have 2 questions about that.

1. What is that spring for?

2. Do I have to put it on the new drums?

I have included pictures below of the old drum, new drum, and the crack.

Any help will be appreciated.

Thanks in advance,
Mike