Crank bolts need tightened to torque spec. Typically something on the order of 35-40Nm IIRC. Get out or buy a torque wrench if you don't have one--crank bolts are one of those things Shade Tree Mechanics tend not to tighten enough. Make sure you're tightening the crank bolt and not a dust cover.

https://www.parktool.com/blog/repair...icle-section-4