Not really "maintenance" but for anyone who's never changed their truck's original springs I would suggest jacking up your truck by the frame perhaps once a year because you might discover something really important. see pic...
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
see pic...