I purchased a used 391D CTL last fall and it just hit the 50 hour maintenance point. I got all of the points re-greased except 2, the 2 which connect the hydraulic ram to the boom on the rear of the machine. I raised the boom and locked the safety stud out and lowered the boom back down onto it. First, neither fitting would allow any grease in. My electric grease gun over pressure valve released on each side. I assumed I had 2 bad grease fittings. Today I pull them out, put them back on the gun and they work fine, the grease is flowing normally through them into the trash. Then problem #2 arrises: I can't get them threaded back into the holes straight. They go in smoothly and without resistance, they don't appear damaged due to cross threading. Does anyone have a clue what the heck I am doing wrong? Does the boom need to be in a different position?