That sounds like a BAL accuslide if it has 4 cables, 2 on each side that you can see when open.
I was not aware they made a hydraulic version. We have had 2 and they both were electric motor driven.
If cables have snapped twice that tells me something is way out of alignment or binding up somewhere. The Accuslide system is usually almost bulletproof unless it was installed incorrectly. It sounds like you need to go to a service dept who has techs that know the system.