The jacks that will not retract may need to be replaced. I just did two of my jacks for the same reason. There is a very large seal at the bottom of the jack cylinder. Over time, this seal will constrict around the cylinder. This is a slow constriction process and will continue to get worse over time. Spraying helps in the short term, but nothing will help in the long term except replacement.
There is a way one can check to make sure it is the jack and not a valve. With the jack no longer retracting (but no fully retracted) manually open the valve for that jack. If the jack retracts fully, the valve is the problem. If the jack remains wherever it was, the jack will need to be replaced.
Lastly, check the jack springs. Are the last 5 coils of the spring straight or tapered into the hook part of the spring? If they are straight then replace the springs. If they are tapered, they should be okay.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours