reel maintance

I use three Shimano stradic spinning reels [ 2 years old ]
for bass in golf course ponds and salt water fishing in local tidal creeks.
Two 2500's and one 4000.
I'm having problems with cranking systems--they often almost lock up as I
try to reel in. I have tried opening crank handle system and adding oil or
wd 40 but this only seems to work for short periods.
Any suggestion for maintaince would be appreciated.It is no fun to be
sitting in Kayak on a nice 21 acre pond and cussing.
Joe the elder









two