Brake servo

[jls]

Does anyone know the difference between a saab 900 and a saab 9000 non abs servo. I have fitted a 900 servo (got it cheap) to my s2 but cant get anything to work. I have a suspicion the servo rod is shorter than a 9000 and hence not enough travel on master cylinder. Any info appreciated or else I may have to go down the mk3 fiesta route (Shame because I managed to also get a brand new saab 9000 master cylinder) Cheers John