If you can push hard, and put the seal IN THE CASE FIRST, you should be able to push hard on the cover and then start the snap ring and then use a screwdriver or something to feed it into the grove all the way around. Prying is needed to get it out, but I have put them back in without having to pry. There is actually a special tool that's sold for that acculumator cover. I think it's usually about $10 or so. The tool just makes it gravy gravy and sooooo simple. But the biggest key is, set the O ring IN THE CASE FIRST. Most people put the O ring over the cover and try to get it in. That'll never happen without damaging the O rings.