I'm swapping out the front brakes in my 94 to the larger brakes found in the LS years. I've been able to find a set of knuckles, however, they don't come with the calipers or brackets. I've resigned to having to pay the core charge for some new calipers, however I need to get bolts to attach the caliper brackets to the knuckles. Does anyone know the bolt size, thread pitch and grade?

 

Do you have access to a thread chaser or can rent one to determine the kind you need?

I highly doubt you'll get a response on here since most people arn't able to answer a question so specific. Best advice is to buy the complete setup if you haven't already spent the money.

One other thing you might want to try is call the dealership. Sometimes they have access to info like this.

 

Yeah, I had resigned to doing that, I have thread chasers so figuring out the size of the hole isn't going to be that big of a problem once I have the parts, I was hoping to avoid doing that so I could consolidate this job more, but it's not a terribly big deal. Thanks for the advice.

 

So did you find the bolts you need? I ordered mine through Fastenal, if you want I can check if they still have what I got on record and let you know. GM is useless when it comes to finding specific bolts.

 

15MM bolts 1-1/4 inch long 4 required use lock washers and lock tight

 

Yeah, I had to get them through the dealer. Luckily, the people at my local dealer are somewhat competent. The bolts were 12x1.25 mm, and 42 mm long, grade 10.9. The local Fastenal said they didn't have them and couldn't get them. Darn things cost about $10 a pop, however. These were for a '98, which is what year knuckles I got, so everything else was as well.

In related news, I actually just did my brakes today. Most everything went fine. I had to bend the metal brake lines in order to get them to line up with the new hoses and their brackets. But I really hit a snag attaching the hose to the right caliper. I couldn't get a good seal and kept getting leaks. I took everything apart a saw that the bolt hole in the caliper was stripped, so I had to swap the caliper out for a new one. An hour or two later, same deal. Turns out I forgot to get banjo bolts for the new calipers. While the diameter of the bolts was the same(10mm), the thread pitch was different(1.25mm old, 1.5mm new). I had to get a heli coil kit(further expanding my costs this project) and put it in the caliper. Everything sealed fine after that. Oddly enough, I didn't have this problem with the left side, although I have more heli coils should it arise. I'm feeling a little dumb about forgetting about that bolt, and a little disappointed that I spent the time painting the first caliper, but there's not much else that can be done about it. All in all, however, it's mostly done(I'll have to go back a paint that left caliper at some point) and I'm happy with the way it turned out.

 

http://www.fbody.com/tech/details.cgi?id=30

Here's the page that shows just about everything.