I checked over the search but didn't find what I was looking for. I'm considering the C5 upgrade on all 4 corners but need some answers first,
1. Will my master cylinder supply the pressure for the bigger brakes?
2. Does the C5 rear rotors work with the C4 emergency brake?
3. Will my aftermarket A molds clear the calipers okay?
These are the questions that come to mind, if there are any other issues please list them.

 

It's fairly easy to do a C5 front brake conversion as there are kits available for that. Vette Brakes has a kit. Or you can purchase the C5 calipers, rotors, caliper brackets and get the adapter bracket separately. Everything is a straightforward bolt on.

As far as the rears, I not really sure if that's worth the effort (and cost). The C5 rear rotor diameter is very close to that of the C4 and the pad surfaces are about the same in terms of size.

The C5 uses an internal shoe parking brake as does your 85. The rotor has a built-in drum just for the shoes. I'm not sure what the drum diameter of each, but there could be some effort involved to get a C5 parking brake to work.

I have a C5 front brake setup on my '87 and I have no issues with the master cylinder. You would meed a different brake bias spring in the MC. Doug Rippie has them and you would need the non-ABS spring for your '85.

Aftermarket A-mold style wheels will clear (they are required for this brake swap). You can use your existing front brake hoses on the C5 caliper.

For my brake swap, I used Z06-specific front pads and Hawk HPS pads in the rear. I also use stock rotors as track days can eat up pads and rotors. So far, this combo works well for street use, autocross and track days. Use good performance pads, a good DOT4 brake fluid, and you should be happy with just the front C5 brake upgrade.

 

C4cruiser got the rest, but for #2, the answer is "No, not practically".

The C5 rotor won't work w/ the C4 caliper. So you have to use the C5 caliper which doesn't have the integrated e-brake mechanism. That means you need to use an internall expanding, drum-type e-brake. Only the early C4 rear brakes have the internal "drum" E-brake, but the sizing is different, the mounts are different...it would take a LOT of fabrication to make the C5 rear brakes work and have a functioning E-brake....and all you get for the work is more heat capacity -no better "braking". Heat is not a problem on the rear brakes generally, so overall....not worth it.

 

Midnight's 85 has the early drum style emergency brake. If the C5 rotor has the same inner diameter (I don't know if it does) there should be no issue. It will require the adapters to mount the calipers. CF member 1976LS1 fabricates the adapters for front and rear. He could probably answer any fitment questions.

 

Dont waste your money.

If you want a conversion that will give you better brakes do a c6 z06 brake conversion

Otherwise just upgrade to 13" j55 fronts and hawk pads all the way around.

 

Don't you need at least 18" wheels for the C6 calipers?

 

When an "early car" is discussed I don't believe the "don't waste your money applies". The J55 comment certainly doesn't. The C5 aside from the more expensive adapters for the early cars I would think a very practical way to improve.

Your A-molds will work likely as mentioned. You need to just refresh your rears, there's way to much involved in doing anything for the rear. The "bias-spring" I think is an owners decision and maybe not a requirement. All hydraulics need to be in good operational condition for any of it to work.

The C6Z06 comment was foolish also I believe maybe for any C4 unless you're obsessed with "appearance"! Would it be a performance increase? Undoubtedly if done right but at what expense?

 

Ahhh......

 

That is misleading b/c the C5 brakes DO provide a benefit that the J55 can not. There is a place for the C5 upgrade, though I don't think it is here. Which makes the C6Z recommendation even more ridiculous.



No. 17" wheels work. I have 17" C5 Z06 wheels with mine. I have read (but not tried it) that the Amolds word fine.

 

Thanks to all who responded, it's good to hear I can leave the rears alone, that will save some money. I already have Hawk pads, (blue box), and the DRM bias spring so all I really need is brackets & front components. Good deal, this project will be easier & cheaper than I expected.

 

I found if I ordered C5 ZO6 calipers, rotors and brackets from eBay the cost was cheaper than VB&P.

 

***edited*** i forgot that the early c4 cars brakes are different.

If it was a later model (88 or up) than i would argue...

 

I'd like to hear this argument's "reasoning". You're saying that on an '88^ car there is no benefit to the C5 brakes?

 

So you are running C6 calipers? It's a mod I've considered but decided against because of the wheels.

 

I am running C5 calipers. They are dimensionally about the same as the C6 base/Z51 caliper. If you were talking about using a C6Z caliper, then you MAY need an 18" front wheel....that I don't know for sure.

 

I understand there are issues with some 18" wheels and the C6Z06 calipers. Regardless of wheel or brake type considered you need to always check the dimensions involved with the particular package desired. There's no generic "these will work" comment that should be considered fact.

 

The J55 brakes were available as part of the Z07 suspension option. The J55 front rotors were 13" in diameter as are the C5 front rotors, but I think they were slightly thinner than the C5 rotor.

And with trying to add J55 brakes to an early C4, you still need some sort of custom adapter bracket. And I think that the J55 caliper abutment bracket is different than the standard C4 brake piece. Finding that J55 mounting bracket could be a problem. The C5 mounting bracket is easier to find.

In any event, going with a larger front rotor really depends really on what you want from the braking system. The early C4 system works well once you find good performance pads, add front brake cooling ducts, and a good DOT4 fluid.
Another place to save is Rockauto. They have C5 calipers and rotors at a good price. One thing about the C5 calipers is that the only difference between the standard caliper and the Z06 caliper is the color. Z06 calipers are just powder-coated red.

 

I agree the are about the same diameter, but the are not just "slightly thinner" than the C5 rotor....