1949 Willys Jeepster

I say backwards instead of in reverse because the same thing happens when coasting backwards in nuetral.

When I backup, in reverse or neutral coast, i get about 20 feet and it abrupts halts almost as if i hit something. No issues moving forward.

I dont know a lot but i was told by seller that it has a new clutch and I even have the old clutch in a box. I'm thinking brake shoes.

Thoughts?