Nylon Washer Question

This is my 2nd keezer build and this go around I’m using all MFL fittings on CO2 lines and beer lines.  Do I need nylon washers on the beer lines too?

I think you only need nylon washers on steel to steel MFLs.  The QDs I have already have a plastic end, so they don’t need the nylon washer.  Metal to metal will leak without.

Excellent point.  I will put them on the metal to metal connections.