its not necessarily the psi but the fact that to deal with those pressures you have to switch to skydrol. Luckily I have no issues with it as long as I keep it out of my eyes so its not a big deal on that front. However, it is toxic to the paint and painted floor of the hanger. Then like Don said, add in the 1963 time frame when the parts were made and the fact that you can't get new ones any longer and I'm forced to hunt for replacements that themselves are far from being perfect. I have 5 brake master cylinders that install behind the rudder pedals. The problem is the cylinder walls and the piston edges are worn from years of use and none of the cylinders are perfect, so I keep switching (which is a huge pain in the ass) the cylinders to try to find one that doesn't leak.
I have replaced most everything on the airplane at this point so most of the leaks are gone, but its just a huge pain in the ass to get to everything in order to fix it. Just very frustrating.
Glenn