I have an early 3406b 3ZJ where my number 4 pump is leaking fuel around the bushings. We just got this truck going. Truck has been sitting for while. Anyway, I’m wanting to replace just the oring(s)for now. I am hoping that this will fix it temporarily..... through the winter, so that we can make some money with it, then possibly have the injection pump itself completely rebuilt in the spring. Truck shows to have around 830k on it. Engine is in good shape elsewhere. No leaks, idles smooth, etc. I’ve read several posts here and elsewhere on this, however my question is if I’m only replacing the oring..... do I still have to center rack? Or can it still be done as long as B&P is not removed? I do have the adapter nut for the bushings and the compressor tool to use. Appreciate and thank y’all for any and all feedback in advance.