What I do is lay down on my comfy work cushion (a foam dog bed that got replaced by a newer model) next to the mower, then I reach up and push the pedals with my hands to spot the pivot points. Anything that moves gets hit with my spray can of white lithium grease or Tri-Flow chain spray. Shoot it right into the butt-crack of the pivot point. Doesn't matter too much what you use, as long as it's thicker than WD-40. WD-40 has it's uses, but it doesn't lubricate or protect well enough for this.
I actually don't know what WD-40 is good for. I've had a can sitting around for about ten years and it's still full. Anyone?