Despite all of the commercially available reproductions of the T800 skull featuring a braided hose topped with a curved (90-degree) elbow joint, my research pointed towards the original T800 skeleton featuring a hose that attached vertically to the underside of the skull, without an elbow fixing.
The original T800's steel tendon was vertically connected to the base of the skull, without an 'elbow joint' at the top
Steel-Braided Flexible Monobloc Tap Connector
Steel-Braided Motorbike Brake Cable
Compression Reducing Set
For the rear piston, I raided the supplies at the same DIY store that I obtained the pair of Steel-Braided Hoses from, and ended up buying a plastic pipe and a wooden rod that snugly fit inside the pipe. In addition to them I also bought a couple of packs of 'Compression Reducers' to act as a cap to the piston. Finally, I glued in position a marble at the top of each piston to act as a simulation of the ball joint. Although not 100% screen-accurate, I felt that the pistons were a close enough reproduction to do the job.
The piston parts after being coated with primer
And a coat of the same Gloss Black Enamel Paint as used on the other skull parts