As far as the crank is concerned, it's recommended to use emery cloth or other fine wet/dry sandpaper with some valve grinding compound and simply grind off the deposits on the crank shaft journal. This is the method we use for Conrod replacements. Emery cloth is good stuff, and with the compound it should polish up those aluminum deposits on the crank in no time.
As long as you have no gouges or deep cuts in the crank it should certainly be reusable.

As for the Piston Pin, these are typically held in with clip rings or "C-rings". The newer pumps, however, use "spade"-like retainers that look like a "sun" (for lack of a better descriptor) with rays and has 6 little points. You can see this in the attached photo as well. If THIS is the type of retainer you have then it's a one-time use retainer and you would simply take a punch and hammer the Piston Pin out with force. In that case you'd have to replace the Retainers, obviously.

I hope this helps!
- MTR

Per Campbell Hausfeld (who actually makes the unit):

"The journal on the NEW crank is 1.76” in and the biggest part of the rod is 1.89”.
You also may check the top of the rod to make sure it is not egged out by the wrist pin.

I hope this helps!

- MTR