Wilwood calipers wont center over the rotor on both rears?

[Erik Beckett]

So, I just finished 2 legs of the power tour and had to quit due to both back rotors wearing/grooving on the outer 1/4 to 1/2" of the rotors. This is on a 1968 Camaro with a stock 12 bolt and a brand new Wilwood disc brake kit with internal parking bakes. I tore into it tonight and for some reason the calipers are not centered over the rotors squarley from top to bottom. While looking at the rotor through the top of caliper opening, its obvious to see that the top area of the caliper is centered but the bottom of the caliper needs to come out some. The rubbing is coming from the caliper just after wear the pad stops on the rotor! I have shims for between the caliper and the bracket but that is only going to draw the caliper in more and need it move out on the bottom. I did my aligning with all the lugnuts on tight and no pads installed.

I am not sure how to shim out he bottom of the caliper? Do I have to shim out the bottom parking brakes assembly from where it bolts to the rearend housing? Or do I have a worse issue like bent axles or something? Again this is one both sides as well and only on the outer side of the rotors.



Thanks, Erik

[dontlifttoshift]

Pictures are worth a 1000 words. Sounds like the calipers aren't square to the rotors.....wrong axle offset on the kit you have?

[Erik Beckett]

Here is a pic of the caliper trying to get centered over the rotor. I am using the 140-9315 kit from Wilwood which is a 2.75" offset kit. I purchased it from Frank at Prodigy. I know you can shim and pull the caliper back into the rotor to center but how do you shim to get the caliper to move out and away from the rotor. It is bolted directly to the axel housing, unless I shim between the axle housing and the brackets to move everything out some? Which does not sound right to me.

[nine lives johnny]

Man it looks like your bracket is messed up. Where did you get the kit. I would advise on not shimming the bracket as it might be allready damaged. Try inspecting the bracket and the mounting points. That much run-out is crazy. Also check your rotor. Does it always look like that? try spinning it and see if it's excessive rotor runout causing the issue.

[Erik Beckett]

I just measured from the back of the bracket to the axle flange and the difference is a 1/4" more at the bottom then the top. Something is out of whack. I hope its not my axle flanges!

[nine lives johnny]

it's probably your bracket.

[Erik Beckett]

I am not ruling out the bracket either but how ironic would that be that both sides are the bent the same. And for that matter, how ironic would it be that the housing ends are bent the same too. I have another eyes coming over today to see if he can see anything different. He has built some Goodguys contenders so hopefully he will figure it out.

Thanks!!!

[Apogee]

Can you take a straight edge across the back of the housing flange and measure to the rotor to check for parallelism? I've seen GM 10/12-bolt housings further out than that from the factory, but not typically on both sides of the same housing, but I guess anything is possible. The more you can rule out, the easier it wshould be to find the source of the problem.

Tobin
KORE3

[Erik Beckett]

Tobin, this is essentially what I did and found that the top distance from bracket to wheel side of rotor was 1/4" narrower then the bottom bracket to the wheel side of the bracket. I believe this is all going to come down to me having new ends put in on the housing. I was hoping to avoid this if possible. I do not see why I cant just shim between the bracket and housing with some small spacers. All this is doing is holding the emergency brake and allowing the caliper to center correct? No spinning parts or anything. I might try it to see if straightens up the caliper. If it does then it might tell me the housing ends are bent.

Thanks, Erik