One of the. arms on my Roadmaster Sterling hitch was stuck and so was the lever. It could be retracted only by using a 4-pound hammer.
I contacted e-trailer and they suggested soaking it in soapy water for several hours. That removed some dirt and the arm was slightly operable. I then repeatedly squirted silicon lubricant down the arms and that loosened them some more. I let it sit for a time and repeated the process. Finally, I repeatedly squirted lithium grease down the arm working the arm after each squirt. Finally, it then worked flawlessly.