hifi engine

Ortofon AS 212 tone arm : hydraulic cueing device problem

I own A S600 turntable from Telefunken (German made ) with an Ortofon AS 212 tone arm . There are some problems with the Hydraulic Cueing device (also "Hi-Jack" called) Problems are: losing oil and going up and down too slow . Have you some experience ? How can i open this ? Or dis/assembly pictures .
Many thanks from Belgium