Oh, that reminds me...forgot to mention this.
You can clean a PS reservoir screen, and honestly, I think you'd have to have had espresso ps fluid and seriously decaying hoses to really clog it...but it can be cleaned despite the legend I've read here and passed along. Someone says something believable sounding, written in proper English, and it gets passed along.
Anyway, remove PS reservoir from it's hoses, remove phillips head screw at the bottom of the reservoir, take screw out, take reservoir to a utility sink and rinse out to your heart's content with soap and warm water. Let dry, attach screen back. You can't take the screen out, but you can clean it while it's inside. It will just roll inside sort of. It's a 2" high 'puck.'
Replace gasket on cap, replace hose clamps after maybe trimming 1/2" off each hose. Done