Tost brake bolt shears off

I am wondering if others have experienced the shearing of a Tost brake
bolt resulting in brake failure - I'm speaking about the bolt which
extends from the hub and is secured to the aircraft frame (not
the bolt which extends for the wire lever attachment). I experienced
such a failure on my latest landing with a month-old Tost unit - I was
puliing more strongly than usual on the brake but not nearly as hard
as I could, and certainly not as hard as I would if it had been an
emergency situation. I was amazed that such could produce a bolt
shear - I would have thought that some other brake part would fail
before such a
relatively thick bolt would, but I am no mechanic. It makes me wonder
about the quality of the parts Tost is using. Is this a known/common
point of failure?

Jack Glendening