I'm on my third one in 10 years

[NGK]

This may be of interest.
In the last 10 years of owning my 280SE, I have gone through 3 aircon tension belt adjustment brackets.
I just replaced one on the weekend having been snapped at the bolt hole. Has anyone else had this happen?
Could someone suggest a remedy perhaps? Luckily I had the last one rewelded and had it as a back-up in the tool box. Maybe the tension is too tight, although when pressing down with finger, it travels around 15-20mm (at a guess).

cheers
NGK