I am asking for suggestions on how to free up the 1/2" quick disconnect fuel supply line to filter. It is stuck. Could it be a seal(s) and if so might lubrication such as WD-40 help? The return line disconnected correctly. It had sliding movement. I am using a "disconnect" tool from Lisle. Thanks in advance.

+++ 2003 GMC 2500 HD Duramax 175K Stock +++

1. Instrument cluster replaced with GM and then rebuilt by Module Master after the GM replacement failed.
2. Lower body corrosion fixed; bed liner applied on skirt.
3. Light "white" smoke during idle presumably unburned fuel. No increase in oil level obvious.

Overall a reliable truck. Good starter cold or hot. 18-mpg overall (75% Highway) lightly loaded. The injectors are the only disappointment. I hope to replace and have talked to Kennedy. I continue to be preplexed by the LB7 injector design / failure and the supposed filtration issues.