Prep work is the key to good concrete crack repair. For smaller garage floor cracks, clean with a wire brush and vacuum with the upholstery attachment. One of the nicest crack cleaning brushes I’ve found is the Forney Wire Scratch Brush. It’s shaped into a “V” or arrow at the top making it easier to push into small spaces. This brush has carbon steel bristles that will make short work of concrete repair preparation. Check it out on Amazon.