There's another case the same in old threads. There is very tight paper thin clearance between the wheel and surrounding plastic well in the case, so the tiniest shaft mounting difference can cause scraping, as well as any deformity in the wheel arm itself and it's pivot shaft mounting, if the wheel on the end is scraping. You could try just reseating the wheel arm in it's snap fit socket. You might just scrape a bit off part of the wheel arm or the well, polish the pivot shaft, or use a very thin copper type washer as shim on the shaft to push slightly sideways. Regular flat washers are rather thick, but there are thinner ones in specialty hardware section in some stores. Scraping only when near full depression into the well shows how an angle is involved and very small tolerances. The problem is locating exactly where the scrape is and what direction to shift with such small dimensions.