4800 Binding issue

[BRF MATT]

I am having issues with my 4800 binding on the Y axis. Machine is about 6 years old. It is level, I have replaced the bearing cassettes, belts, cleaned the rails as well as possible. They do show some minor imperfections due to the water and debris that gets on them. Seems the worst on the home end when leaving datum position. Gear racks look ok. Removed the motors and manually move the gantry- seems free, not sure how much resistance it should have. Any ideas? Hate to just replace the rails and have the same issue.