My company just bought a used Okuma MB8000-H. The machine came in pretty bad shape but overall runs well. After about a week of running, the High Pressure Coolant Fitting that attaches to the back of the hydraulic cylinder on the back of the spindle/drawbar broke. I actually had a 1/2" JIS nipple and replaced it rather easily. After 3 shifts it broke again, so I replaced and made sure all my lines and moving components were not hitting or rubbing on anything including making sure I am not hitting the cast frame on the "Y" axis when it goes as far down Negative the machine will allow. 3 shifts later the fitting again broke. I now took the cylinder apart cleaned made sure everything in it was working properly and put a new fitting in. I also checked the thru coolant pin and spring inside the nose of the spindle and checked the drawbar clamp force. After everything checked out I let the machine run. Again the fitting broke. I am now out of ideas. What could be causing this??? I am not sure where to look next... I did turn the high pressure coolant down from 1,000PSI to 400PSI and made sure all tools that used it were not plugged. Please give me your thoughts, any suggestion is worth trying at this point.