Off topic but need help on a 928

A friend of mine has an 85 928 Euro model and he was telling me that the pop up headlamps have some type of leveling device in it that operates on fluid. He has Bosch H4 head lamps not Hella or what a US model would use and I guess the leveling system is unique to Bosch lamps on the Euro spec car. Well the problem is one of the hoses that actuates the leveling device cracked and the fluid has leaked out. He says it may be a silicone type fliud. I have no clue, I was thinking maybe someone else has heard of this and can tell me what kind of fluid it takes so he can refill it and correct the problem. Thanks....TargaEuro...