My 98 V70 R is getting due for a timing belt replacement - 137k, belt was done at 70k and I figure that 140k should be time for belt #2. I plan on replacing both the idler and tensioner pulleys as well due to age and mileage, but wonder if I should do the water pump and tensioner also while I'm in there? Your thoughts and suggestions are appreciated. thanks

 

Yes, you should do both pump and tensioner, and blue boxes (genuine Volvo) are your friends.
here is Ozark Lee's wonderful write-up;
http://www.matthewsvolvosite.com/for...hp?f=1&t=19831