McFarlane Aviation Products has developed a new tool to determine Flap track wear. McFarlane developed this tool to positively indicate when the flap track is worn beyond service limits.
Flap Track Wear Gage
Use to determine if a Cessna flap track is worn beyond service limits.
Flap Track Wear Gage Instructions: Run the gage plug along each slot in each flap track while verifying that the gage will not enter the slot. Reposition the flaps as required to gage the entire length of each slot. If the gage enters a slot at any point the track is worn beyond service limits. The diameter of the gage is .6035 inches (diameter tolerance +.000/-.002)Periodically verify the gage diameter by measuring the age diameter with a calibrated micrometer.
The tool tells you if the slots in the flap tracks themselves are worn beyond service limits. This would tell you if you need to replace the flap track itself.
The red part of the handle is simply the handle area where you hang on to it.
The circular ball area on the other end is what you run along the slots in the flap track and if at any point that circle drops down into the slot the flap track is worn.