What Are These Rings For (nerf Bar Mounting) ?

[mokeman3]

So my 2010 Silverado regular cab short box is about 1 month old now, - about 1,200 miles now.

 

I decided to get a spray-in liner (Full Metal Jacket brand), and a canopy, and step bars (Nerf bars?) Here she is:

 

 

However these G-damn Nerf bars/step rails have been a PITA! big time. They have been making all sorts of noises that sounds like something was left up in the frame or fender or something.

 

I've had it! - driving me bonkers, so I decided to take them off and check it out. On the front half, I found these sheet-metal spacer rings between the top of the step bracket, and the bottom of the lower half of the frame mounting bushing:

 

 

Also, (and a little disturbing), the metal in the lower bushing half was dished out on both sides (front bushings only).

 

So does anyone know what these rings wound be in there for, and what would have caused the lower bushing halves to dish out ? Not sure you can see the dishing from the photo's, but I beat them back flat between two large sockets, and put it all together without the rings, but did put one square construction "plate washer" between the bracket and the bottom of the bushing. Not sure why, but I did.

 

Noise be GONE!. But later, I got to thinking, and it dawned on me, crap, maybe they where in there for "expansion sliders" or something. i.e. the Nerf bar expands, and instead of bending/warping your frame/cab all to hell, maybe the bracket is designed to "slide" on the edges of the ring? I dunno. Should I put them back on? What's the dealy-O here ?

 

PS, sorry about posting this in this forum, but it is "sorta" suspension related, and besides, I think (hope) that there are more mechanical minds in this forum that would probably have a better insight into this issue.

 

Thanks,

MM3