Father-Son 1974 Duster Project

Decided to buff it out by hand and let it be till the shop can get the car in.

Now, I am planning to swap in some new used window regulators to my Duster. The windows are a bit clunky going up, and not as bad going down.
Any tips on what to do to these regulators before they go in?

Any advice on how to ensure a successful upgrade?