Shimming calipers and wheel studs

[dcozzi]

I shimmed the Wilwood rear calipers on my car today. It took all day to get them centered. One side perfectly centered. I mean perfect. The other side was maybe .005-.010" off. Will this be a problem as long as the caliper is parallel to the rotor?

I did not have washers smaller than .035" to make it absolutely perfect and had to sand some to .018" just to get the calipers parallel to the rotor on one bolt on both sides. I think the powdercoat on the rear end housing flanges affected the bracket alignment.


On the front of the car with an aluminum hub, is it correct to use a threaded stud rather than a press in? I figured a threaded stud is the way to go with aluminum. I am going to get it machined for 1/2" ARP wheel studs since it came with 7/16" Dorman studs and wanted to make it stronger for track use.

[Apogee]

Perfectly centered isn't necessary. I don't know what Wilwood's specifications are but most calipers are designed such that even 1/32" one way or the other isn't a big deal. You just want to make sure that you're not going to have any interference, pad wear, or piston travel issues. I think most people would consider .005" to .010" from center as perfect...or at least close enough not to matter.

As for the studs, you can use either a press-in type or screw-in type stud in aluminum, although the added contact area of a threaded stud certainly has it's advantages. I don't know what weight car this setup is going on, but 7/16" are not optimal for track use for most pro-touring builds, 1/2-20 or M12x1.5 are typically a much better choice.

Tobin
KORE3

[dcozzi]

Tobin, thanks for the info.

Funny thing, the hubs I am using are Kore3 units I have for my C4 brake upgrade. The guy I bought them from got the Dormans instead of the ARP.

Wilwood will "never say never" with alot of their advice since their stuff is engineered and guaranteed to work a certain way and I understand their point of view on that. They also say a caliper for 1.25" rotors "should be" safe to use with 1.10" rotors, but do not guarantee it, if you know what I mean. Once again, I do not blame them one bit.

The car is a 1970 Camaro and used to weigh 3660lbs with 1/2 tank of gas and me in it. Hopefully it less on this build since I have already got rid of some weight with the 3-link, tubular A-arms, etc..

Once again, thank you for your experienced perspective. I am a brake novice but, for the rears, I took alot of time measuring, aligning, used red loctite, lock washers and safety wired the bolts. Should be good.

[Apogee]

Sure, no problem. It sounds like you've put a fair amount of thought and research into this already...certainly better to do so up front in my opinion than trying to decide how it ultimately failed after the fact. Better not to fail at all whenever possible.

Tobin
KORE3