Originally posted by XID:
...I don't know for sure what size the nut was, but we used a 1-1/8" wrench, which had a slight amount of play, but never slipped...
Just in case if anyone's wondering, 28 mm socket fits the idler arm bolt perfectly. Or, yes, 1-1/8" is the next closest.
I was never able to find 28 mm socket or open/close end wrench at Sears. I don't remember where I found my 28 mm socket, but the maker of it is:
stanley, not craftsman.