In very cold weather(20s) door goes up part way and stops. Have to assist it. Cleaned off grease and used silicone and WD40 to lubricate. How can I give it more cranking power? I see an increase/decrease arrow. Do I turn the brass fitting(1/4" threaded) or the black plastic housing? Which directs give more lifting power, clockwise or counter clockwise? 1980s vintage unit.