1995 Ford Mustang Wheel Smells burn

Hi guys! I have a question for you and I hope you can help me. I own a 1995 Ford Mustang V6 3.8l. My rear seals broked so some oil was spilled on my rear wheel on the left side. We repaired the seal but the rim was still dirty. One day we took the highway and we did about 1hour of highway and when we stopped my rear left wheel smelt burn and was hotter than the others. So I checked if the hand brake was jammed on the rotor but the hand brake is fine. After I though that it was the oil that came hot and smell that. So I took brake cleaner and cleaned the rim. But the other day we took the highway too and same thing but this time my rim was clean. I don't have a clue what the problem is. I hope you guys can help me..

Thanks!