elgy

I am in the process of changing the fuel hoses between the engine and the hard lines on my '78 928. I have the kit from 928 Motorsports (hose and clamps), the 7.5 mm hose goes on the high pressure barbed fitting fairly easily, but will not go onto the return line fitting. Am I right in thinking that this hose is a larger size or am I just not pushing hard enough? If a larger hose in necessary what size?

Thanks in advance.

P.S. - faced with fittings that I was incapable of unscrewing I am changing the hoses in place... I will do a write-up when I'm finished. This method bypasses both the difficulty of unscrewing the fittings and the problem of the threaded fittings leaking after assembly.