Problem with upper ebrake cable anchoring

[ScottH]

Recently installed all new brake cables in my 65 c10. All works good except the upper cable will not anchor securely in the clamp that holds it just below the pull handle. No matter how much I tighten the bolt, it slips through when I pull on the handle. The rubber coating is getting shreaded from slipping in the clamp.

Has anyone run into this issue & found a solution?

Any info, suggestions, or help is greatly appreciated.

Thanks