The ML4 was produced over a couple of decades and in many versions, so it would help if you can provide details or, even better, photographs. The more you tell us, the more we can help.
Have you searched this forum for threads about the ML4? There have been plenty, containing a great deal of information. There is overlap between the ML1,2,3 and 4 so it is worth searching for all those as well.
Have you read about the ML1,2,3,4 on Tony Griffiths' website lathes.co.uk?
Does your lathe have a serial number (stamped on a raised panel on the bed, below the headstock)? Does it have tumbler reverse? Do the cross slide and top slide have dials? Is the spindle nose thread 7/8" diameter or 1 1/8" diameter? Which version of the tailstock have you got? (there were three, to my knowledge).
George