Don't even have to do that. The only line that needs to be disconnected for an entire rear end change is the rubber line that connects to the body of the car. Usually easier to remove it from the distribution block on the axle.
Also, there were some design changes in 7.25 axles. The early ones reatined the axle out at the hub, the later ones used a C-clip. The later ones also have a bigger axle bearing. You need to be careful swaping parts. My recomendation would be to swap entire axle assemblies if you can.