Is that what it is? The spindle? Anyways this happened about Monday or so. Could not figure out what that thump thump thump noise was, so I hoped it would go away by itself. It would only make it 10% of the time I drove. Thought it was my tranny acting up again. I heard a grinding this morning so I took my wheel off (drivers front) and the 2 damn caliper bolts had totally shaken free from the spindle. Has this happened to anyone else? This was probably not life threatening like causing the caliper to fly into the rim, or I have someone up there looking out for me.

 

How long ago where the calipers off?
New pads or rotors or bearings or bushing change recently?

 

On my ls1 brakes one of those bolts backed out and caliper swung out and ground the **** out of one of my rims. Locktited them all and torqued them down and no problems since. Scared the heck out of me when it happened though.

 

Happened to me too. Only it ruined my brand new 17" Fittipaldi rim, broke the stainless steel brake line, the e-brake connection and left me stranded and leaving a big puddle of brake fluid in the middle of a busy intersection.

I was moving around say 45 mph and it just went.. thump crack BANG! The car must have jumped up 2" off the ground when it locked between the disk and the rim... arghhh

 

Sounds like the caliper bolts were not properly tightened. You are lucky you caught it before serious damage or accident occurred.