My Bosch 5" ROS has recently become very hard to handle. I have had it for a few years now and have always found it to be quite easy to handle and yet powerful. However, lately I have barely been able to keep it on the work surface. I can see that it moves in both the circular as well as random motions still. I took the pad off to see what I could and found that there is a rubber ring that rides against the back of the sanding pad to direct the airflow for the dust collection through the proper ports. I found that the ring was caked with paint residue. Not thinking that this was relevant, I cleaned the residue off anyway before I put it back together. It was much more manageable, for a while. It went back to its difficult behavior fairly quickly. I took it apart again and found that the ring was again covered with paint residue, (BTW I was trying to sand out some primer). I cleaned it again and it ran better. I do not understand why the paint residue would cause it to behave the way that it does. Has anyone had the strange problem? I was thinking about putting a very light coat of silicone spray on the ring to see if that would prevent the paint from sticking to it. Does anyone have any better ideas?
SteveP.