Quote Originally Posted by SubGothius View Post
Before you replace the pump, just try out that new belt you got. Could be the old belt looks fine but is actually worn/glazed/hardened/etc. from age enough to impair its traction against the pulley.
Appreciate the suggestion. It turned out that although the belt was in good condition the tensioner was maxed out and the belt couldn't be tightened anymore. After trying three more shorter belts, I found the correct length and there is no more issue. I will be sending the pump back and using the money for other parts.

Thank you!