The design of the one you have does mean that if that red cover plate is not air tight then you will lose any precious suction. Is there a gasket on the red cover? Its very clean inside too. I would have expected the paint to be a bit chipped inside from all the dust and dirt.
It works ok yeah. Picks up things quite quickly and does give the carpet a brushed look. The fan outlet is quite large so there is plenty of room for air flow. As you can see in the photo the bag is inflated when pushing to and fro.
They were never very powerful machines, however here should be enough airflow to inflate the bag. After a good fast push across the carpet the fan should take about 20 seconds to slow down and stop. If you can get it apart I would drop some oil on the fan bearings. Can you show us any photos...
You would use the existing oval clip from your original U4014 Outer bag. You need to feed this into the stitched channel on the bottom of the replacement bag......
So the Neptune lives on as the Zelmer Aquawelt. Just looked at the spec and they have now improved on it by making it a carpet washer and a water filter vacuum, or if you prefer it can be used with filter bags instead of using the water filter. I knew the Neptune reminded me of something...
These were the original Disposall bags first seen on the 638 Senior and the 1334 Junior. The end of the bag that fits on the dust tube came pre-folded and stapled to fit the dust tube. To empty the bag you removed the metal bag clip at the other end. The next generation dustbag did away with...