The Kelsey-Hayes Disk Brake Swap Thread

Very useful post. Thanks for taking the time. I don't see a concern with using the grade 8 bolts instead of special "shoulder bolts" for 3 reasons:

1) I just replaced front pads on my 84 M-B 300D, which has a similar design - fixed caliper and rotor that bolts to inside of hub. Actually, a lesser design since 2 pistons (not 4) and solid rotor (not vented). Anyway, the 2 bolts that attach the caliper look like the ones you used. I didn't notice any special shoulder or tight fit in the caliper holes. Don't 73+ A-bodies have a caliper bracket that bolts to the spindle? Does it use special bolts? I recall my 2002 T&C is like that and has regular bolts.

2) Unless the factory bolt was a very tight fit, more like a tapered ball joint stud, I don't see how it would prevent radial play. They would still rely on the clamping tension providing interface friction.

3) The forces on a brake caliper are among the most predictable of any in a car. There are two limiters - when the pads slide on the rotor and when the tires slide on the road. A rough calculation gives <1000 lbf when the tires skid. That is trivial in the world of 7/16" bolts.