Yes I can get replacement parts for the windmills, I can get you a new wheel, or pivot, or mast head or tail. The first thing I need to know is if your damaged windmill is made in the USA. If you have one of the Chinese copies the part I have may not fit. It you have a garden windmill that has blades that have come loose or are missing you DO NOT have an American made windmill – this just plain does not happen with the Made in the USA windmills. The most common failure with the windmills I carry is 15 years or more after purchase the bearing may fail.
If you have a garden windmill that has blades that have come loose or have flown off you have one of the Chinese copies. You may be able to replace your damaged wheel with the USA made wheel, however the changes are the shaft sizes will be different. Also the mast head often fails with the Chinese windmills. Sometimes you may be able to just get a new wheel. If the shaft size of your pivot is different you will need to get a new pivot and when you replace the pivot you usually will need to replace the mast head.
By the time you replace the wheel, pivot and mast head you are getting close to what it would cost to just get a new windmill. (Replacing the wheel, mast head and pivot will cost a lot more than you paid originally for the cheap Chinese windmill)
What can you do with the old windmill tower if you do not want to replace the damaged top parts? The Chinese made garden windmill towers are not bad, they are a lighter gauge steel than the Made in the USA ones to be sure but the tower itself holds up fairly well, it is the wheel that commonly fails with the Chinese models. Also the mast head will often fail.
I have just learned that the weather vanes I have available will fit in the mast head of any of the windmills that have a 1/2 inch shaft going into the mast head. Just remove the top windmill parts, get a roof, deck or pole mount weathervane and put the shaft into the mast head. Add some set screws and get the weathervane level and now you have a tower mounted weather vane.