Brake caliper bolt replacement?

Is there any reason why I shouldn't use a standard grade 8 bolt for my ZJ disc install? I got the calipers and backing plates but dont have the bolts to attach them to each other. Does the bolt need to be smooth with only threads at the end like the factory bolts or is a fully threaded bolt fine?

Mike

the caliper is designed to "float" on those bolts-- you definitely want to use the specified smooth bolts.

Ummmm... you sure, Shorty? Every caliper that I've looked at has a sleeve over the caliper bolts. That's what the caliper actually rides on. Deformed threads would allow the pins to wobble, though.

No reason, IMO, to go with a grade 8 bolt either. There's relatively little force on the bolts, they serve to hold the pins in place. The braking force is directed into the knuckle. And, the bolts are known to strip out the threads in the knuckle as well. Even with a grade 8 bolt, you aren't going to get any more holding force on the pins.

although I'm visualizing mine ('88 AMC calipers and knuckle) and not a ZJ assembly, I can say they "float" on the bolts. There is a rubber boot that is fixed in position on the caliper and a thin plastic sleeve to aid in reducing friction, but no other moving parts. If the ZJ bolts are different, than I'll shut up and let more knowledgeable people add their experiences.

Make sure they are not metric parts before buying grade 8s... if they are metric, you want ISO Property Class 10.9 instead.

If RockAuto is correct, it's the same bolt/sleeve (guide pin) that the front calipers use.