Like I said before,I have lost count of the number of these things I have changed and I've been doing it since 1980. The gas remains in the oil because it's in the struts and the spheres and like I also said,Don't guess,just undo either of the hoses from any of the spheres,poke a wire into it and see how far it goes. Besides Where else did the foam come from?
So simple yet I continually here all these weird and wonderful ideas on how to diagnose bad spheres. On later model cars Like Neds W124,the Springs are supporting more of the cars weight than a W123 Wagon and the car will ride OK but you tend to feel more jolts than normal.