how can i stop my the motor on my vax6130 from making unusual noises?

my Vax 6130 sometimes makes an unusual lou dnoise from the motor section. i have looked at stripping it down for further inspection. i am a trained maintenance engineer and i quite often repair many household electrical items, but i cannot see how to strip thie motor section down. can anyone help me? maybe suggest a where i can get a schematic from.