[Richard]

The only way to test the integrity and pressure of the bladder is to relieve the pressure on the hydraulic side.

Here’s why. The system is closed, assuming no leaks in the RAS hydraulic lines or cylinders. It was initially pressurized to some level, say 225 psi, which compressed the N2 in the bladder to 225 psi. Now if the bladder ruptures, again assuming no leaks in the system, the pressure will STILL be 225 psi.

To make the situation way more interesting, with the accumulator mounted upside down, the N2 has now traveled to the high point in the system. But it’s still there, and the pressure will still read 225.

All that has happened if the bladder ruptured is the hyd fluid and N2 did what gravity told them to do.

If this is the case you must be very very careful if breaking into the hyd system. Normally in an all hydraulic situation, as soon as you crack a fitting the pressure relieves due to the incompressibility of the fluid. But now we have a bubble of compressed gas that will expand and produce pressure until the pressure reaches 1 bar or 14.7 psi.

I commend both of you for digging in and trying to test and figure this out. I know NOTHING about the ZF system, my commentary is based upon working with hydraulic systems in industrial environments. So yo have to take my input with a boulder of salt, not a grain.