Common place is the return lines. Either the o-rings under the return T's wear out after a while or the rubber return lines from one injector to the next dries out and cracks, and then the leaks occur. Another common problem is simply screwing the fuel filter on wrong. Yeah people think they are the shit and they can get a damn fuel bowl on right, no they can't. It just kinda happens every now and then.
But seeing its an 85, a leak in the return lines wouldn't suprise me at all.
Edit: J-rod kinda covered all of that.
If you need new return lines, you can get it all from
www.mwfi.com, or Midwest Fuel Injection. They are good people.
Also, I have a leak in mine from when I switched out the stock mech lift pump for an electric Holley fuel pump... I just bleed the fuel bowl everytime. That depends on how lazy you are though.