I bought a use Proform 1280s elliptical machine. It makes a loud clicking/clonking sound when in motion. We've taken off the back cover and we can't seem to tighten the screws because they are stuck in place.... not sure what to do with it now. We can see that the left pedal has wiggle room where it attaches to the wheel, but the right side is nice and tight. Also the resistance level doesn't adjust... I'm not sure if this is a related problem.

Exercise & Fitness - Treadmill Doctor - Proform 1280S Interactive Trainer Elliptical Ramp Wheel