Express Oil Pump

I've got a '78 express and I took the oil pump off of it a few years ago since it was clogged with dirt. The gear inside the pump was stripped, so I bought a used one off the net.

the thing is, I'm not 100% sure that I have it together properly. I have the old one for comparison, but it's in pieces too. I have a fat (about .25 inch) shaft inside of the body with a gear the size of a quarter and there is a spring on it that presses against a funny piece. This piece is a fat cylinder with a skinny shaft that goes inside of the larger one, as far as I can tell. It has two "ramps" on it which I presume ride against the cover, which has a bump with a little flat spot on it that corresponds with this ramped piece.

Does anyone have any experience with these pumps? I'll take a picture if need be.

Re: Express Oil Pump

Leon Swarmer /

Have you looked at the pics in the manual??

Re: Express Oil Pump

It's hard to tell when these are working right.

The shaft the goes into the motor needs to seat so it drives the gear inside the pump housing.

You've already taken the pump cover off so make sure the shaft that comes from the moter actually turns the pump acentric (I think it's called). As it turns as you suspected it gets pushed in by the bump in the cover. This is where it gets its pump pressure to move the oil along.

I saw it as quite a lot of trouble to move such a small amount of oil but It is important that it moves a mesured amount and that the amount increases as the motor goes faster.

I found a simple way to make sure it's working. Put it all back together and put it in your motor (oil the crap out of everything that moves). Once you have it assembled, open the bleeder screw until you have a clear flow of oil with no air (really really make sure as the pump will not prime with any air in it).

Once you have let a small air gap bubble get in the line that goes to the intake. Start the motor and watch that it moves along the tubing toward the intake. Remember it only needs to move a little at a time to provide the right amount.

Let me know how this worked out for you. This is how I did mine. I had two pumps for comparison and they both worked the same way.


Re: Express Oil Pump

50plus - , I looked at the diagram but it was of no help. Thanks

Mike - Everything moves, and it seems that I have everything in order according go your description. I will try that method once I get the rest of things sorted out and I'll just use premix gasoline to make sure that there is some oil in the internals :)

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