I'm fixing to pull the boat on a long trip so I figured I would give the bearings a shot of grease. It's a 2007 champion boat trailer. The front axle is easy it has normal bearing buddies and are easy to grease. The back axle has brakes and I can't figure out how to get to the greas fitting if it even has one. I can remove a metal ring and a large spring but can't get any further. There is a black cap covering where the fitting should be but I can't get it to come off. I am afraid to pry real hard for fear of braking something.
I have a picture on my phone but don't have my computer handy to put it on here.
Anyone have any ideas?

Is it a small rounded cap ? Tap it with a hammer as you spin the wheel..

Sounds like a torsion axle.

Just my thought, but if I was going to be going on a long road trip, I would be putting in all new bearings and races and packing new grease in if it hasn't been done in the last two years.....you don't wanna be the guy on the side of the road with a blown up hub/axle

just my 2 cents

Not sure what you are describing; so someone may have put oil bath hubs on it. Then there is no need to fool with it. Most are good for 50,000 miles and factory jobs are good for 100,000 miles.

- If it is a button cap the size of a quarter; then you use something with a heavy sharp edge like a small chisel to get between the cap and the bearing housing/hub.
Work your away around the cap until it pops off, be genital if it is plastic.

- If it is a cup type dust cover then you use a large set of channel pliers to rotate it after you have used the chisel method above to loosen it a bit. It must be loosened some or the channels will dent the cover. Rotate back and forth until it pops off.

- A set of bearing pullers at Harbor Freight will help on many of these problems other than pulling bearings. Still have to loosen it some to get the hooks to catch so it will pull.

Or at least pull all of them apart, clean and repack replacing rear seals and replace bearings and races if needed....