Partials can be more effective than full ROMs; try both full sets of partials as well as some partial reps after reaching failure. Partials can create growth faster and avoid injury by focusing on the sweet spot of the motion that pays the biggest dividends and blast through sticking points where full ROMS won't. What you experienced with the leg presses.
Good examples of exercises that are actually better using partials. Can also try using different parts of the ROM as the partial:
-Box squats, going down to about parallel-better than full squats, from my experience.
-Preacher curls-leave out the very bottom and top of the motion, both to avoid straining the tendons/elbows and to keep the tension on.
-Flys-don't go right to the top.
-Hacks-don't lockout at the top.
Etc.