First, I admit I borrowed heavily from others here on TBN, especially MadReferee and Barnboy. Second, I have yet to try them out, so don't know how or if they work. But here they are.
I wanted to make them removeable, and adjustable, so I used pins to attach them to the rake. Also that allowed me to turn the rake backwards and still use the wheels.
I made split rubber washers for height adjustment. I sacrificed part of a rubber horse stall mat. I'm not sure how they will hold up, but decided to give them a try. It should be very easy to adjust, just pull out a washer and move it above or below.
Thats All Folks! Just having so much fun I wanted to share. Feel free to critique my work, (I know I need practice welding), as I am willing to learn! Note: In one of the pictures you can see my chain box fastened to my quick hitch that I copied from someone here on TBN /forums/images/graemlins/laugh.gif
I have a Massey Ferguson rake and your casters look better than the factory made castors that cost me a fortune. Let me know how your rubber washers work out. Good work!