The right rear did not drag when I was checking them. I believe that the anti vibration valve on mastercyclinder could cause this. It kind of makes snese for the concern. If the abs unit was bad or had some kind problem there might be a light on. I have no light and the abs works as should. If the relief hole inside master cylinder were clogged it would affect two wheels not just one. I am looking little farther and will make a choice of were to go to next. Thanks for your help and the link to repair manual.