My '38 Chrysler has the Cavalier rack conversion. It was in there for several years working fine, but I had to disconnect it to do some other repairs, and now I can't get the pressure line to stop leaking. The leak is at the 16mm o-ring fitting on the pressure side of the rack. I've put 3 different o-rings on; tried tightening it more...tightening less...I just can't get it to stop. I'm using Dorman #099-011.2 o-rings that are 7/16" o.d. and 5/16" i.d. Is there something I should know about o-rings that could be my problem? This is turning into one of those things that seems like it ought to be routine, but ends up taking forever.