[AllanC]

The factory service manual shows the front and rear risers (attach to roof and hold horizontal rails) are fastened with a machine screw. There is a riveted nut installed through holes in the roof at each riser and the machine screws thread into these riveted fasteners. I would guess that the riveted fastener that goes through the roof is installed before the headliner is placed in the vehicle. Installation of the through the roof riveted fastener is critical to prevent water leakage.

There might be some additional reinforcement in the roof applied to vehicles that have factory roof racks versus those that do not. The only way to determine that is to remove the headliner on your target vehicle at the salvage yard and inspect its roof rack mounting.

This post has been edited by AllanC: 18 May 2008 - 10:07 PM

[alvin]

Rivet-nuts are the fasteners specifically designed to be installed when only one side is accessible.
The important thing is to take accurate measurements of where the holes are located, and also to use
sealant to prevent rust. The factory rivet nuts have 6 mm thread and insert into a 10 mm hole. I believe they
already have sealant applied.
The holes should probably be drilled in steps and a drill stopper will be necessary.
Rivet-nuts are not too hard to work with. I used two (factory parts) to add a grab handle on the right-side
front pillar. In that case, the holes were already there, which is obvioulsy not the so with the roof.

This post has been edited by alvin: 19 May 2008 - 07:44 AM