3208 injector pump

Can,t quite figure out where your saying the leak is.Is it the injection housing area or just what part is it there that is leaking?

its the injector housing

The throttle shaft where it comes through the housing has a lip seal & then there is gaskets in other areas an or "O" ring seals so if you don,t have a parts book to pin the leak down I,d say go to the Cat dealer & have them look it up for you then you can get the seals or gaskets you need.

You said low pressure cup. Are you referring to the shutoff housing on the top were the solenoid goes. There it would leak out the spaghetti hoses down the left front corner of the engine (if it still has them). That is the piece that you have to remove the top of the pump to get to.