Leak from high side pressure a/c line.

When I removed the cap of the high side a/c
pressure valve on my 1995 Chevy Corvette LT1 I
immediately noticed a strong leak coming from the
valve until I screwed cap back on. I was told to
replace the entire line. It seems I should be able to
just replace the shraeder valve. Can I get some
opinions please. Thanks for any assistance!