Look towards the bottom of this page for all of the info you need.
http://www.ausjeepoffroad.com/forum/...=140297&page=2
In my experience the Nuline idlers are the way to go, they last much better than Dayco idlers, even though they're all owned by the same company from memory.
The ribbed idler the bearing can be replaced easily/cheaply. Also the bearing in the viscous heater pump is likely to need replacing, the details for this are also on this page, or copied below. The bearing isn't cheap, though, be prepared for a $50 price tag from memory.
The bearing inside the heater clutch is also a standard style bearing similar to most A/C compressors and a number for that is 35BD5222DUM18A (OD=52mm, ID= 35mm, Depth=22mm)
Jason