bluepearl92

I ran in to an issue while upgrading the front calipers on my 92 this weekend and was wondering if anyone else has had this problem. I purchased the C5 adapter brackets from Pacific Northwest ZR-1, rotors and pads, and a used set of C5 calipers from the forum. When installing the caliper, the inside (engine side) of the rotor hits firmly against the caliper, to the point that you can't turn the rotor. It appears that the rotor needs to be spaced out about 1/4 inch to be centered inside the caliper. The brackets only fit one way, and I see no way to get the clearance needed without spacing out the rotor from the hub. Did I get some junk brackets, or am I missing something?

VetteMed

Probably ought to check with the vendor to see if you got all the washers that are needed for mounting... of course, in the case of that particular vendor, it'll probably be weeks before you hear back... good luck.

c4cruiser

Are you using the C5 caliper abutment brackets? These are the ones that the calipers bolt to. You cannot use the C4 caliper brackets.

bluepearl92

Yea...it took me 4 months to get these brackets. I'm wondering if he sent me the wrong ones. What do the brackets for the early C4's look like? Would this cause the offset that I am missing?

bluepearl92

Yes, I'm using the abutment brackets that came with the C5 calipers.

tshirttom

You will have a problem when trying to fit sawblades or other C4 wheels because my experience was the same...the caliper will hit the rim. You have the right kit but you will need to get spacers or upgrade your rims as I did.

bluepearl92

I have A molds on it, and they clear fine...no issues there from the front/side/back/etc. The issue is with the rotor contacting the caliper (the abutment bracket, actually) on the inside.

c4cruiser

He doesn't have that problem; the inside part of the rotor is hitting the inside of the caliper.

For the OP: did you get the washers with the custom brackets??

Installation instructions are here. There are pics of the adapter brackets in that link; do they look like what you received? IIRC, they are left and right specific.

bluepearl92

They look similar, but this picture here http://www.pnwzr1.com/images/Brakes/..._installed.jpg appears to have more of an "inset" to the caliper mounting area than the ones I have. What I received from them was the two brackets (painted black and no writing on them) and 4 bolts/washers (two bolts and two washers for each bracket). They are right/left specific, and I installed/removed/trial fitted/etc to make sure I was installing correctly. They really only fit one way that I could see. I won't have pictures until tonight of the brackets I have (at work right now).

corvette95

Use the caliper bracket washer from old c4 bracket behind the middle bolt (40mm bolt) so it doesnt hit the bracket then use bolt,washer,bracket,washer, nut on bottom larger bolt. You somehow you dont have the washers in the right places.

bluepearl92

I will look at doing that. So it will be OK to space the bracket out? That's not going to weaken the mounting point? Here are the brackets I received:

bluepearl92

But if I use the washers anywhere but BEHIND the rotor (to push the wheel/rotor out), it's going to push the caliper out more toward the wheel, and the rotor is already hitting the caliper. There is no way to space "back" the caliper so it centers on the rotor and doesn't hit it by using washers. Is that making any sense? It's like the adapter bracket needs to be thinner, or have an offset more toward the motor side of the car.

corvette95

I JUST went through this the past weekend, wish I could explain better via the board. Email me at corvette95@charter.net and I will give you my phone number and masybe I can help. You have to re-use your old caliper bracket washers. You DID get new C5 rotors didnt you?

corvette95

You new calipers will ONLY work with c5 rotors, your old 12 or 13 inch c4 rotors will NOT work

bluepearl92

Yes, got C5 front rotors. I'll be in touch, thanks a bunch!!