http://icas.org/ICAS_ARCHIVE/ICAS2006/PAPERS/048.PDF
http://williams.best.vwh.net/172RG_POH/7-28.jpg
I remember from training back in the 70's that wet lines into cockpits was to be avoided at all costs as the effect of a leak was quite dramatic. We've all seen the films with the WW2 pilot getting covered in hot oil.
The quoted 210 has a working pressure of between 1000/1500 psi, modern systems have 3000 psi plus. Nobody wants that in the cockpit.