Windscreen Wiper Motor - Removal & Replacement

I have a 1971 Chrysler Valiant Regal (Australian), on the same design (some variation) as the 1970 Plymouth Valiant (USA). The wiper motor is located on the outside fire wall (not under the dash like some US models), so it is easy to get to. I want to replace it with a cleaned up reconditioned unit, but I am hesitant to undo the holding bolts because I don't want to be disconnecting internal parts that maybe difficult to reconnect. Has anyone done this replacement who could give me an idea on what is involved??? ROB.
Thanks to all you blokes for the heads up on this query....very much appreciated and I will take on board all details...her goes.....ROB