Look it and the rail over for a manufacturers mark, then find the company on the internet, and ask them for replacement parts.
There were many companies that made drawer glide assemblies over the decades, and this one might be out of business, so be prepared to buy a new assembly and replace that broken one.
ED
There were many companies that made drawer glide assemblies over the decades, and this one might be out of business, so be prepared to buy a new assembly and replace that broken one.
ED