How is the cranking speed. You say you do not have fuel pressure at the bleeder screw. I would guess your 88 just has the single filter and the pipe plug above the 5/8 inch hex which you unscrew to change filters. If you have this set up put a good gauge in there and see what you have for primary fuel pressure. Do you have an elbow on the front side of the pump 1/8 inch pipe thread on the end that goes in the pump, 3/16 inverted flare on the other end? This elbow is a special elbow that has a small orfice in it that causes resistance to flow which creates the pressure on the low side. 5-6 pounds of primary side pressure will do it. I will bet that 90% of the pumps have the seal broke. In fact if you have the early Z model pump on an older tractor the smoke screw was on the outside.!