Well now that the 810 is running right I've been driving it more often and I can't help but notice there's a crazy knocking from the right front corner when driving over uneven pavement.
I took a look under the car the other night to see if anything was obviously wrong. It didn't take long to find the culprit....
So I got busy researching the idler arm. As I'm sure you know, these arms are somewhat unique (at least in my experience) in that they use replaceable bushings on the pivot shaft.
Good news: I found the Nissan part number (48544-H1000)!
Bad news: I called my local dealer and they told me it's discontinued.
Good news: They also gave me the phone number of the next closest dealer that shows some in stock!
Bad news: They're 450 miles away.
Good news: I called them anyway and they were happy to ship the bushings to me!
The part number is for a single bushing and two are required. A pair with tax and shipping cost me just under $24, vs roughly $130 (plus tax and shipping) for a complete new arm from several online retailers.
I removed the arm and took it apart, cleaned it, painted it and reassembled with the new bushings. I also replaced the threaded plug with a grease fitting. I'm not sure why they wouldn't have done that in the first place.
That pile of crumbs is all that was left of the old bushings, shown with the new ones for comparison.
All back together, no more noise and the steering is a bit more responsive
I did read somewhere that the replacement bushings only fit if you have a Nissan arm to start with. If it's already been replaced with an aftermarket arm either the pin or the bore is a different diameter.
All I can confirm is that my arm had a Nissan logo on it and the bushings fit perfectly.