Ho Bob, yes you are wright, the bolt can vibrate out if not corectly tightend, but also can the bolt brake if over tightend, this is the story of all dealers. What tipe of warenty/garenty do the give on there work, you can nail them, if not compliing, contac there head office and ask the same questions.be calm and polite, as these poepel do not like to hear screeming and agrovated customers, hope you can get sorted
louw olivier
February 2015