I have a 2007 H2. Just bought a set of 4 Roof Rail Assist Handles, GM Part #12499199, cheap cheap on ebay. They didn't come with the mounting hardware (which I knew) and no dealers or GM Parts suppliers will help me in even knowing what size, type, etc the nuts/bolts are as they want me to buy a full set from them, which I won't do because they are 5x what I paid. Does anyone have have photo of the OEM stock nut/bolt to attach these things? I already took handle to Depot and it will accomodate a 1/4" 2.5" bolt but I really don't want to install fender washers so it's held in on the rail.
Any help is appreciated.
Thanks,

 

I know this is an old thread, but if anyone is still looking for pictures of the actual Roof Rail Assist Handle hardware and a source of a great substitute, here you go.
For a great substitute, get some "No Spring Spring-Nuts for 1/4" rod", such as part number SNWO1420 from Garvin Industries (https://www.garvinindustries.com/han...-nuts/snwo1420) and some stainless 1/4"-20 x 2 1/2" screws. The aforementioned spring nuts are almost exactly the same dimensions as the factory nuts and will work with slight modification. Grind down two "catty corner" edges of the nuts to approximate the trapezoid shape of the factory nuts as shown in the attached pictures. This will allow the nuts to swivel when tightened and catch under the lips of the rail channels. The 2 1/2" screws are just long enough to catch the top of the threads on the nuts when the nuts are laying in the bottom of the rail channel. The screw holes in the handles are offset from center. Place the handles on top of the rails so the screw holes are closer to the outside of the vehicle.This will allow the handles to properly be positioned on top of the rails. Since the rail channel lips are wider on one side than the other, it is important to position the nut inside the bottom of the rail channel so that the pointy ends will catch the underneath side of the lips for strength when you tighten it. It would be best to get socket head screws to allow to be torqued down with a hex ("Allen") wrench instead of trying to "put the tighten" on a Phillips head screw. I suppose you could put some Loc-Tite on the threads to save someone's windshield behind you in case the screws loosened up. Of course you could make your own nuts by cutting, grinding, drilling, and tapping some flat stock, but this other way gets you stainless without as much hassle.

 

Excellent reply.