Engine Belts And Pulleys problems of the 2006 Mercury Mariner

My Mercury Mariner's idler pulley has already broken three times in the past five months. There must be a recall on this vehicle. The car is very good and too strong for that thin bolt in this part. Luckily, the fourth time it happened, the Ford dealer didn't charge me for the new part, which also broke off two weeks later. It has also broken two belts already. Trying to solve the issue, I went to metric bolts and nuts, in wakefield, MA, and bought a higher grade hardened steel bolt/screw, and it also broke off a week later. Once again, two days ago, my mechanic put in another hardened steel screw. He added a nut near the bearing, which makes a squeaking noise, but it has not broken yet. I am now afraid to drive it far from home, because I have been towed so many times already. I have researched the internet and realized that it is a constant issue. Some people have reported the occurrence of this issue 17 times in less than a year. It is also the same frequent problem with Mazda tribute, Ford escape, Ford fusion, etc. What does it take for a recall? help! help! help!.