Today was dump valve day for me.

When you remove the old dump valve, do not turn the nut. It has a flange with burrs to prevent loosening. If you turn the nut, the burrs will cause some stress risers on the smooth plastic and could crack later. So hold the nut while you turn the bolt head.

When you put in the new valve or new seals, do not use the steel nuts and bolts they give you. Use stainless with self-locking nuts, or at least stainless or brass nuts on the steel bolts. And use anti-seize. Being an overkill guy, I like a large-area washer under each head and each nut to distribute the load a little better on the plastic. Slightly longer bolts (2") are required if you do the washer thing.

I like Valterra valves because I can get spare seals to carry.

Take a look at your sewer plumbing and imagine a tire tread coming loose and whopping around. My coach has a plywood guard, sort of, but I am going to put in a bigger thicker one. Lots of horror stories out there.