Mike's 1993 Dodge Cummins Truck Blog

Not many parts to the pump shaft.

Notice how the 2 key ways line up on the same side of the shaft? A few more parts like the cam plate and the plunger also align to these keys. The 2 rubber dampers just fall out when you lift the gear up the shaft.

Here is how to put the rubber dampers back in place. Lube them up. Then push them in one end first. Then just push the other end in.

Use vaseline to hold the small key in place. Do no put the large key in until much later.

The small key engages that key way at about the 7:30 position.

Here is how the pump shaft looks as it’s being dropped into position. The lower end of the key is pushed in slightly so it will engage the keyway much easier as the the pump shaft is slid into position.

Here is the pump shaft in it’s correct position. That vertical oval slot in the back ground, has a round hole in the center of it that is out of focus. That hole needs to be centered so the large pin can be put back in.

With the pump shaft removed, it’s easier to work out the front seal. I tried removing the front seal with the pump shaft still installed. The seal removing tool just wouldn’t work. I’ve had good luck with it before. At least this way, the pump shaft is removed so it can’t be gouged or scratched trying to take out the seal.

Putting the pump body in a vice helped this operation a lot!! There is a lot of rubber behind the metal of the seal. So I had to push very hard with the screw driver to get a good bite on the metal. It pried right out.

Make sure you take pictures along the way. Lots of them.

Remove springs and their rods/washers. Take out the collar that I’m holding here, and then remove the plunger shaft which is still installed.

Here is the cam plate. Reach in with a magnet and pull it out.

Here is the cam plate.

Remove the rollers and their beveled washers. Note that the beveled washers are placed toward the outside of the rollers.

Rollers removed. At the 3 o’clock position there is a black clip snapped over a pin.

Remove the clip carefully with a flat bladed screw driver and a magnet or it will fly across the room as soon as you pry on it!!!

Remove the pin with a magnet that was covered by the clip.

The pin has a head on it.

Pull the large pin sideways as far as it will go.

The magnet is used to then pull this drive assembly up some.

Then the driven assembly can be removed. Don’t let the large pin fall on the floor.

Make 2 marks on the nose of the pump where your key is located. That way it will match the location of the key way on the gear back on the engine. Remove the large woodruff key.

I have used fine tiped dikes for years. They allow you to grab the key. They also provide nice leverage to remove the key. Note that genuine Cummins woodruff keys have dimple on the side of the key that makes the key fit tight so it won’t fall of the shaft when re-installing the pump onto the motor.

Take the magnet and pull up on the pump shaft. It will slide right out only if the woodruff key is out. Notice the large thrust washer and a small key.

Keep the pump shaft clean and safe. There was a slight varnish buildup where the seal rides on my pump shaft. I used my finger nails with a paper towel in between to remove the varnish. The sealing surface has to stay polished. Do not scratch or file it.

All that is left are the pump vanes. In front of them is the shaft seal. I didn’t remove the pump vanes since the inside of the pump was sterile when I took it apart.