Tektro Brake Piston Tool

My bicycle's Tektro brake pistons were sticking and I needed something to allow one piston at a time to be extended for cleaning. To use, first remove the brake pads and wheel. Then use wedged spreaders or a  plastic tire tool to push the pistons back into the caliper. I printed and used this model: https://www.printables.com/model/585123-bicycle-disc-brake-caliper-piston-spreader.

Then insert my tool onto the caliper from the rear with the depression toward the piston you want to extend. It will generally stay in place by itself, or you can use a rubber band to hold it. Pump the brake lever carefully as many times as needed to extend just the one isolated piston. Remove the tool and clean the piston with isopropyl alcohol and lube with a dab of mineral oil if desired. You can use the wedges to press the piston back in, then reïnsert the piston tool and pump the piston back out, repeating the cleaning and lubrication as many times as necessary. Flip the tool over to work on the other piston.

I printed this on a Prusa Core One+, PLA or PETG, 0.4mm nozzle, 0.2mm layer height, three perimeters, and 25% grid pattern infill. You can print it standing vertically or flat, but either position will benefit from supports. I printed mine flat.

The pictures show my first attempt in orange PETG prusament and second attempt in white PLA. The only difference is some chamfer and filleting in the second version posted here.