There are three cylinders on each side. The center pump cylinder is the horizontal one inboard of the electric actuator screw. This cylinder has twice the fluid capacity of the brake cylinders that go from horizontal to almost vertical position when fully open.
The rod end of each airbrake cylinder connect to the speedbrake panel and the cylinder ends connect to a machined yoke and tube that slips over the electric actuator screw.
When the actuator is extended,it brings out both airbrake cylinders at the same time. The pump cylinder (rod end) is connected to the aft end of the screw.
As the actuator pushes out the top and bottom brake cylinders ( the ones you see
almost vertical) the piston rod end of the pump cylinder also moves.
In this way, the
pump cylinder pushes fluid into both brake cylinders at the same time through the
manifold and hoses. When the brakes are open at various positions the fluid can transfer between the top and bottom cylinders.