Fusor Forums

I have flushed my pump twice with clean oil, yet it still produces a poor vacuum and the oil comes out very, very dirty. I have decided to take apart and clean my pump manually in order to get the maximum pull. I will be taking pictures in order to show the process and I will be posting it on here later. I was wondering if anyone had any tips or information that could assist me. Thank you.

Sounds like your pump was used for some nasty work in the past. How low does it pull? Gotta' TC gauge hooked to it? How long did you run the newer oil changes? I assume you totally blocked off the inlet as discussed in the FAQ when running and ran it for a long time. 1/2 hour or longer?

Richard Hull

I ran it for a sold three hours with a completely sealed up Vacumm --> KF25 to CF 2.75 --> CF 2.75 to 1/8 NPT --> DV-23 either the gauge was broken (highly doubt it as it came from Mike) or I only pulled marginally below atmosperic pressure. I will update this as soon as I finish cleaning it up and let you know the results.

I just finished and I honestly believe that this pump was submerged in a cesspool of sewage and put back together before it was sent to me. I can't possibly even comprehend a reason for a pump being this filthy.

I have hit a roadblock on the project. The vacuum pump is hard to turn by hand, it will turn easily with a small wrench however. I believe that there is some form of dirt and rust buildup in the cylinders and I do not have the systems to properly reassemble the vacuum pump to that degree after finish. How should I continue. The motor is almost flawless however.

I am trying to understand...........You have run the pump already and it would not pull much below atmosphere? If it ran and you changed the oil several times why would it now be hard to turn? It doesn't make sense. Even a terrible pump that is rusty and nasty will pull to a couple of hundred microns...certainly to a torr or so. Need more data and images to help here. You never submitted and image. I am suspecting the gauge now or a stuck blade on the rotor inside the pump.

If it holds its oil and doesn't leak when running, the seals are good. If the pump was that bad internally one would think the seal would be shot.

Richard Hull

Some pumps have an internal solenoid valve to isolate the fore line and vent the pump. If this is jammed on the open position it will be bleeding atmospheric air directly into the intake. Is there air coming out of the exhaust?

Yep that was it, the spring was broken and it was jammed. Thank you.