In the early 80s, cars shifted to low drag disc brakes. For example, the 82-83 AMC Spirit disc brakes were low friction compared to the 78-79 Pacer disc brake pistons. The parts are interchangable so you can upgrade a Pacer to the low friction pistons. What about the D? Are these low friction disc brakes? Are there later model calipers that are low friction. Typically, the low friction pistons slightly retract after application. This could be a spring in the main piston that creates a little negative hydraulic pressure to retract the pistons. Drum brakes used to do this with springs. Bob To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/