Joined: Feb 2012
Posts: 19,362
Likes: 5,503
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Every coaster brake hub I've serviced got grease on all surfaces including brake shoes/disks/rollers. If they're not lubed squeal, chatter and other issues will be the case.
But don't expect that the stopping power will be as great as a rim brake or disk can be. Andy.