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Let’s take it apart

E2M1.5 Disassembly


E2M1.5 - 01Out of the box, this pump gets the same treatment. With fingers crossed, I’m hoping to have better luck with this one. Good working order would be nice, but a complete complement of parts would do.

At this point, I’ve already pulled the motor off. Because it came with a 12″ lead with a broken twistlock plug attached, I swapped power cords on it. It powered up but I could tell from the sound that it had a noisy bearing. Also the pump wasn’t pumping. So I’m 0 for 2 now. Awesome. Time to figure out why.

E2M1.5 - 02

At first blush, this pump appears to be in much better shape. It isn’t nearly as gunky and shows very minor rust. This time around, three long cap screws hold the pump assembly to the frame.

E2M1.5 - 03

With the pump assembly off, I can see that the rotors are driven through a plastic coupler. In the end of each shaft is a groove that the coupler sits in. The motor side of the coupler had been completely sheared off.

E2M1.5 - 04

After removing the seals and cleaning up the frame, I went on to investigate what might have caused the coupler to shear off.

E2M1.5 - 05

I tried to turn the rotors with just fingers and couldn’t. I put a wide screwdriver in the slot and did get it to turn. After turning it a few times, it loosened up. Apparently the sludge and thick oil had caused the rotors to stick. I also noticed quite a lot of debris in the first stage pump chamber visible in the photo above, most likely from the shredded coupler.

E2M1.5 - 06

The oil pump came off next as well as the exhaust valve baffle. The second stage vanes and chamber were in much better shape than the first stage. The exhaust valve goes in the hole toward the front of that recessed area in the top.

There is a shiny thing with an O-ring showing at the upper right corner. That is where the gas ballast air comes into the pump. It should pull right out.

E2M1.5 - 07

One rotor goes in from each side of the pump assembly. They’re bolted together and friction fit into a ring in the middle. To get them apart, I took one of the long bolts and threaded it into the threaded rotor. A few taps with a hammer is all it took to liberate the rotors.

E2M1.5 - 08

This is what I mean about the ring. It is allegedly a separate piece, but I didn’t try to take it off.

E2M1.5 - 09

Finally, the drive-side oil pump. I’ve taken the O-ring off here.

E2M1.5 - 10

This is the front side of the oil pump with the pressure regulator disassembled. Under the plate (where the three screw holes are) is the shaft and a tiny little blade that makes the oil pump go.

At this point, the pump is pretty much completely disassembled. Since I’m not sure when I’ll get a repair kit, I ended up putting the whole thing back together after a good cleaning.

On to Part 2: The Rebuild

posted under Equipment, TakeItApart
One Comment to

“E2M1.5 Disassembly”

  1. On May 30th, 2015 at 5:14 pm Wouter Says:


    Am i glad i wound up here!

    I purchased a Edwards E1M5 pump wich has a badly contaminated oil box, showing signs of rust in the old oil and the inner construction.

    Can you please help a guy out, how to remove the oil box without damaging anything?

    Thanks in advance!!


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