This might be completely unrelated, but I had problem with physics objects leaving their restraints, too. Pumping up ph_fps_max_lock to 180 solved the problem (at a hit to fps). I would also like some "physics superglue" to keep physics objects within their constraints. -Of course this might be unrelated, but I have had problems with sliders and wheels sticking to the axis I've set them. My tests have shown that it is very easy for a wheel to go way out of range of its axis and if they go too far they don't recover (like in your picture. I'm guessing you didn't set your constraints at 45 degrees). I noticed that they are more likely to jump their restraints and do something spastic when close to level geometry.