I purchased curt trailer hitch for my 2014 Audi Q7. I had to first remove the bumper impact bar which comes factory installed. In place of bumper impact bar, the trailer hitch is supposed to fit perfectly. It actually fit perfectly. However the bolts that came with curt trailer hitch were too long to fit in fully. So I ended reusing the bolts that came out of the bumper impact bar. My question is - are the bumper impact bar bolts safe enough to be used on trailer hitch. Will bumper impact bar bolts be able to withstand very heavy loads which curt trailer hitch can carry. Or should I replace these with bolts that can withstand load on trailer hitch. The bumper impact bar bolts color is silverish and the ones that came with curt trailer hitch had golden/yellow color on it
Yes, the bolts should work just fine.
The bolts were providing enough support for the bumper impact bar and would be expected to hold up to a collision/impact without failure ... there's no reason to believe they won't do the same for the hitch. As long as you've torqued them down, they should easily be able to hold the hitch.
The impact bar has M12x1.5 bolt of 50mm length and Grade 8 (8.8) . The bolts that came with hitch receiver are grade 10 (10.9). So the conclusion is I cannot use the bolts from Impact bar because grade 8 is less strength than grade 10. Check this link for info on bolt grades . I ordered M12x10.5x50 bolts of grade 10 online.