Hi Marty,
Swapping the pump is relatively easy.
Look at the face of the bottom of the pump ("pump flange") where it meets the block. You'll see a verticle line scribed across both that serves as an alignment mark. If you don't see the one on the block, it may be painted over -- just draw a new one in line with the one on the pump. If you can't find either one, you'll need to clean the pump flange and/or the block until you can see one in order to find or be able to draw the one on the block. You'll need it for the reinstall.
Loosen the 6 nuts on top going to the injector lines and put them up and out. Loosen the 2 nuts holding the supply and return lines and pull them out. Remove the three nuts on the bolts that hold the pump down. Wiggle and lift the pump out. Remove the gasket from under the pump because you might as well replace it, even if it isn't bad. Some people (not me) find it easier to remove the lines on both sides to get them out of the way. If needed, I just loose the bar that keeps the lines to the injectors tight in position and put it back when done.
Replacement is the reverse of the install with three things to note:
-- There are little rubber ring gaskets that will likely get left in the pump when you remove the supply and return lines (they aren't on the other lines). Don't forget to install these on the tips of lines when you do the reinstall.
- The pump is keyed so you can not physically put it in out of time. You'll see how it works if you look at the gear-line splne at the bottom of the old pump shaft and down into the block after you pull it. Before installing the new pump, you'll want to rotate the shaft on the pump so the spline lines up with the key inside. Just rotate the gear so it lines up. If you want, take a picture of the old pump from the bottom when you remove it, so you can set the new one to the same position rather than eyeballing it otherwise. When you put it in (after putting down a new gasket), you'll need to wiggle the rotation as you put it in until the key lands in exactly the right place and fits in .
-- Once the pump is back in and sitting on the (gasket on the) block, /very lightly/ tighten the three nuts that hold the pump down (including and washers and lock washers). Then, rotate the pump so that the scribed line is again lined up and exactly. Then tighten everything down.
I don't understand what part of your pump is leaking. Can you send a picture where you point at it with your finger or screwdriver or draw an arrow?
There are o-rings on the throttle assembly that available and are easy to remove and replace.
