Vintage Windmill and Wind Generator Forum

I have a Aeromotor 8’ windmill that I recently moved from Iowa to Kansas, using for decoration only. I had the head rebuilt by a professional & we put it up a few months ago. Was quiet as could be for 5 months then noticed that it was making some noise - climbed up and discovered that the oil had mostly all leaked out. Where do I start as far as trying to resolve this?

Can you tell where the oil or bulk of the oil leaked out from? You might check the umbrella washer on the mast pipe nut as that umbrella washer goes only one way to avoid excess oil loss.

Can you see where it's leaking from if so take pics and get hold of the person who rebuilt it.

Where did the oil go? Out of the hub and onto the blades or down the pump rod

I believe down pump rod, as it was wet with oil - I put in some additional oil & thought I might be able to tell better with another look. I would need to pull the head back off to check umbrella washer - correct?

The umbrella washer is properly installed - but oil seems to be running of gears and down the mast pipe. What type of restrict or can I put to prevent oil from drip down the mast pipe?

You can climb the tower and pull the bonnet off to check the umbrella washer. If it is upside down, that can cause excess oil to go down the mast pipe. I think of it as an umbrella or more like a funnel, if installed upside down.

There is a ton of good info on here and the knowledge is amazing. The mast should stick up about 1/8" above the case and the washer should look like an umbrella not a cup.
I rebuilt an Aermotor for a friend and it leaked oil down the mast. What I learned was 2 things. First, when you rebuild a windmill and have it off the mast before you put it back on you should pack the cavity inside the mast hole with grease. The 2nd is sometimes the oil running off the mast washer when everything is clean will run into the hole just below the mast washer. The purpose of this hole is to lube the mast but sometimes it gets too much and will gradually use up the oil in the case. You can put something like a short piece of pipe cleaner in the hole to restrict the amount which gets thru. This is what worked for me on a 1923 A602that I put up at our place.

Sorry I forgot to mention you don't have to take the head off to check the mast washer and mast nut, just the helmet.

Also check the mast nut hole and pump rod for wear if the pump rod is too sloppy inside the nut you'll loose oil.

I had a similar problem. When I installed my umbrella washer it wasn’t centered and didn’t drop down into the recess properly, it allowed oil to leak and was running down all of my tower legs and was not noticed until it was too late. Needless to say, I was pissed! My nice clean legs were now stained! Someone suggested that I install the pump rod which I had not done originally, so when I went to do it, that was when I discovered the cocked washer. I chucked the washer up in my lathe and created a deeper shoulder so it seated better. Seems to have stopped the leaking and now I am hoping the oil will diminish over time.