Vacuum pump rebuild process
Step 1: Tools
The pump has been removed and there are various tools that you will need.
- Small screwdriver
- Sandpaper (300-400 grit)
- 1" 1/8 deep socket
- 15/16 deep socket
- 19mm deep socket
- 36mm socket
Step 2: Cummins Kit (4089742)
You will need this kit to service the vacuum pump. This kit was only about $16 so pretty inexpensive.
This is the two sections split apart by taking the two bolts loose.
Mark where the seal retainer was for a reference point later.
Put the bolts on the bottom of the rear section so that it lays flat on the workbench.
Put the 19mm socket in the hole and pound the seal retainer out.
This is what it comes out looking like.
Make sure to put the coupler disk back into the rear section as soon as you take it off. This will make sure that you don't forget to put it back in first.
This is the outer o-ring that we will be replacing. Simply take it off with a small screwdriver.
This is how the seal retainer came out of the rear section. Flip it over to pound the inner seal out.
Use the 15/16 socket to pound the inner seal out of the seal retainer.
This is the new the inner seal, and this side is showing the spring that is on the inside. Put the spring side facing up on the seal retainer. Put the new seal in the opposite of how it came out. Use the 1" 1/8 socket to install the new seal.
Now install the new outer O-ring and put some lubricant on it as well.
Don't forget to install the seal retainer first into the rear section. The sides are both the same so it can go in either way.
Flip the seal retainer over and start putting it in by hand to start the O-ring. Then use the 36mm socket to install the seal retainer. Look to see if the mark is in the same place as before.
Next, take out the vanes in the pump itself. It is easy to tell which way they go back in.
Sand both sides of the vanes to make them smooth again, and then reinstall them.
Now take off the small O-ring on the pump. and install it with the new one with grease as well.
Now put the two halves back together. It will be very clear when the two will be lined up. The dog ears on the pump will sit into the coupler disk like it shows.