So I noticed a rattling sound on my front driver side the other day. It came and went and happened after I put air in the tires. I thought something might be dragging, but everytime I looked, nada. So I got under it today and noticed I am missing the upper bolt on the driver side front brake caliper! Wondering if my other bolts were loose, I checked the passenger side and noticed that the bolt was on all the way but just spins in place. Obviously, it's not normal to loose a bolt. How tight should these bolts be and has this happened to anyone else? Thanks.

 

Sounds like a DIY brake job gone bad. Someone stripped and did not torque bolts...yikes, makes one wonder what other projects were done to such poor standards?!
Just google for torque values.

 

The caliper mounting brackets 125lb ft. The guide pin bolts 23 lb ft.

 

not a bad idea to check other critical bolts as well. Checked recently and my RR axle nut was loose! According to service records and original owner, this nut has never been off.

 

With some Locktite on the bracket bolts, and a little anti-seize on the guide pins.....

 

It may be the caliper mounting bolt and the guide pin are both turning.

 

125 ft/lb and locktite. Mine are on and off the car frequently, I replace them regularly. Cheap insurance.

 

 

The two guide pin bolts are torqued to 23 ft-lbs. It's important that the threads on both the bolt and the female threads in the guide pin are clean and free of any old threadlocker.

While you can replace the bolts (match them at any Lowe's or Home Depot for size and grade) you can get replacement sets at any GM dealer. There are kits that include the bolt, rubber dust boot and guide pins and grease for the guide pins. These are common to most later GM cars. The bolts in the kits come with a threadlocker already applied. In your case with one bolt simply spinning, it sounds like somebody applied way too much torque to the bolt.

If you choose to reuse the existing bolts, clean the threads with a wire brush and apply some BLUE Loctite/Permatex to the threads and torque to spec. I keep some brass rifle cleaning brushes handy for cleaning female threads like in the guide pins. Brushes like .22, .38, and 12 gauge shotgun will cover a lot of female thread sizes

The large bolts that hold the caliper abutment bracket to the spindle can also be reused. Clean the threads and apply the same BLUE Loctite and torque to spec doing it in two steps (1st to 70 ft-lbs then to 125)

 

The caliper guide pin will turn when you attempt to loosen the guide pin bolt unless you put another wrench on the guide pin hex by the dust boot.

Some aftermarket guide pins have just two flats instead of a hex.