I studied the P-38 nose gear at last year's GML2007 and noticed it had pistons on each side at the top of the scissors link of the nose gear. I am not sure if they are to enable steering only or act as a shock damper during steering also. The page below is a P-38 walk-around where you can clearly see them.
http://www.cybermodeler.com/aircraft...-38_walk.shtml
Some aircraft use a drag-link strut which does not need the link at all. The B-52's out-board single wing strut is an example of this. The wheel fork is angled backwards and thus the wheel turns almost any direction that the aircraft is rolling.
As a volunteer as Smithsonian, I have learned and visualized that most of our aircraft on static display either use 'strut collars' over the piston part of these struts, or have internal machinings replacing the fluid inside, otherwise the pistons would collapse over time so the link would be completely closed. Also some aircraft had strut collars as part of their regular maintenance procedures to eliminate any possibility of collapse. The DO-335 on display has original (1945) strut collars in place.