As I recall (and happy to be corrected) the nosewheel free fall lowering could be initiated by the lever under the co plots feet. To use the emergency system via the lever on the port forward side of the cargo bay you needed hydraulic pressure. This was either with the aux pump running or by the hand pump. As I recall the drill was to try the hand pump first to check that the system held pressure . If you did not and the problem was a leak in the nosegear hydraulic lines the the aux pump at full pressure would pump the reservoir contents overboard before you could blink.
In respect of the mainwheels I have had a couple of assymetric lowerings usually after a winter transit from cold climes. I took the inspection windows off both times and after a while the gear came out to play. Interestingly it was the port gear both times.