Full Instructions Here:-
http://www.pentaxforums.com/forums/pentax-k-r-forum/145847-k-r-e-dial-repair.html
You would need to have a bottle of electronics contact cleaner to do the job, example products here and here.
Good luck if you are one of those victims whom have suffered from that deteriorating product quality and reliability nowadays! :-(
Usual Disclaimer: Try everything at your *own* risk!