Why did clutch fork bracket break ?

[Racer57]

Putting everything back together Thursday. But this is bugging the hell outta me !! 

Why did this break ? One bolt was loose allowing maybe 1/8" gap or was it faulty or did I try to adjust too far or ..................

The bellhousing, clutch and Tremec 5 speed was installed by a "professional" and the bracket has "A Body" stamped on it.  New one is from Brewers and not near as thick.

[torredcuda]

So it`s an aftermarket part? If so my bet is crappy metal as I`ve seen it many times from parts overseas working in a metal fabrication shop.

[Dakota]

My barely educated guess: That looks like a "brittle fracture" vs a ductile one (no deformation or elongation around break).  There was probably a small crack/defect in the metal.   Combined with the relatively quick and high stress applied when the clutch pedal was pressed, that would do it.

If close inspection shows some of thinning of the metal around the break, that would be a ductile failure most likely coming from repeated cycling... it wore out.