Rescuing my Volvo after 3 years parked

[jbg]

I am getting my parts order together and I need help with 2 items:

I cannot easily find a water pump o-ring. I am sure there are thousands of sites that sell them, but I cannot confirm what is the right one. Can someone please reply with a site with a known good o-ring?

The timing belt idlers I am finding are referencing the idler's bearing as a replacement part. Not the entire idler as the part. I am not against that, replacing the idler bearing, but I'd like to know what the bearing ID an OD measurements are. Can anyone provide me this information?

For example, Rock Auto has 2 bearings:

15mm x 35mm x 11mm or 20mm x 47mm x 14mm. I don't have the idler here to measure. If anyone could help that would be super, thanks!