Somehow, over the winter, the suspension of my '55 Bird has begun to creak & groan. It's only noticeable at very slow speed over uneven terrain (or while manually depressing the springs while parked). Oddly enough, the noises coincidently began emanating from front AND rear simultaneously, BUT only diagonally! When the right front & left rear are depressed/bounced, the creak/groan is quite audible, but NOT when depressing the left front & right rear.
The (apparently) original springs & A-arm bushings have 125K miles on them (90K by me), but all the ball-jt., etc. nipples have always been routinely lubed. The car handles normally, and the suspension is silent at road speeds. Inspection while raised on jacks/ramps reveals nothing unusual, but I don't have the strength working alone to depress the suspension and thus track down the source of the noise while under the car. I would likely have to find a local shop with a mechanic's pit, so I could move around (with a stethoscope?) while someone above bounces the Rt. front or Lt. rear of the car.
Now, while the noise is not all that annoying (I suppose I still might likely go to the trouble of locating/applying lube to the source should it continue), I worry that ignoring it might lead to some component seizing, with resulting damage/complications down the road. Has anyone experience/solved a similar problem?

6 VOLTS/POS. GRD. NW INDIANA