Last time I did them they were being a bitch and I ended up flattening a nail down to a flat sharp edge with a slight hook on it. I just hammered it on an anvil but anything hard and heavy will work. The thing worked better then any tool I've seen before to pop the ring up.
try using 2 small screwdivers or something like mike said..........i have found it easier to use 2 because you can hold down one side of the ring while you get the other screwdiver under the other side of the ring and run it around to pop it off
I used a set of snap ring pliers to remove it and it was still a bitch to get off.Got them from snapon man .If you dont have them then it will have to be the old way nails and screw drivers and alot of bitching lol.NO FUN.......
it's a pain in the ass.. be sure to look at the ring closely, it is not cut straight at the end, one side slants forward / and the other side slants back \ you oviously want to pry up on the forward slanting side so you're pick (or tool whatever) can hook it.
i've had the best luck by putting a screwdriver against the side of it somewhere, putting pressure on it so it cant spin, the working on the / side until you get it to pop up. sometimes then (you can just hold it there) and sneek another smal screwdriver under it so it can't lay back down in the groove. once you've got it this far you're home free.
but yes, it's by far the biggest pain-in-the-ass single part in a bronco.