The return line from the suspension is low pressure return. With the engine running the pump supplies fluid to the suspension contstantly. With no load the pressure holds up the suspension, and the rest of the fluid returns to the reservoir. You can take off the cap and watch a stream of oil returning to the tank. When you add weight to the back, the leveling valve moves and ports more fluid to the hyd cyls to raise the car. When the car is level, the valve zeroes out and all the fluid is again put into a recycling stage. I don't suspect a sphere, because they are just shock absorbers since there are no shocks. I'll look for a diagram.

Peter

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