I picked up a box full of high quality compression fittings at a tag sale. They're all Parker and Weathertite. I realize these should never be used on a brake line but what's the thinking on fuel lines (5-9 psi)? I have some with brass ferrules and some with nylon.
My oil pressure guage is the type that has the little oil line that runs from the back of the motor. Ive tried several times but it has always leaked right where the hose goes into the brass fitting going into the motor. What is the trick to getting these to not leak?