c4cruiser

Finally after letting parts sit around for months, I just finished the install of C5 front brakes on my 87. The only thing I was "missing" was a new set of Hoosier A6's for autocross. My old 16" tires had to make do until I could spring for a set of 275/40-17's Finally got those from Lee at HAVOC Motorsports thanks to a great price and free shipping!

For those of you who may not know, this upgrade requires 17" front wheels but the stock 17" C4 "salad-shooter" wheels don't have enough inside clearance at the top of the caliper. So you have to use the ZR-1 style wheel or a wheel that will clear the caliper.

The custom mounting bracket I used is unique to the 84-87 cars. The one for the 88-96 car is a different design. Other than that and the wheels, stock C5 front brake components are all that is needed. Even the early flex hoses work fine.

The install is pretty straightforward, remove the old caliper, pads, and rotor. Clean up any rust or debris on the face of the wheel mounting flange and clean up the suspension as much as you want (gotta look prettah!).

Then using the OEM caliper bracket bolts, install the custom brackets onto the spindle and torque to spec. Lube the guide pins, add the rubber boots and clips into the C5 caliper abutment bracket, and bolt them onto the custom bracket and torque to the same spec.

Slide the pads into the clips on the abutment bracket, slip the caliper over the pads and bolt them into the abutment bracket. Attach the flex line and bleed. Repeat for the other side and you're done. Once I got going, the whole install took about 3 hours including beer breaks.

The total cost for the upgrade (not including the wheels) was around $650.
Z06 calipers 88895128 and 88895129 $113.24 each GM PartsDirect
Pad set, Z06-specific 88952008 $127.00 GM PartsHouse
Caliper Bracket (2) 12455799 $70.50 GM PartsDirect
Guide Pin (4) 12530697 $16.24 GM PartsDirect
Boot Kit, Guide Pin (4) $13.80 GM PartsDirect
C5 Rotor LF, Raybestos Advanced Design 56700 $36.79 Rockauto.com
C5 Rotor RF, Raybestos Advanced Design 56701 $36.89 Rockauto.com
(these rotors have angled vanes, not the straight vanes)
C4-C5 caliper bracket (PNW ZR-1) $105.00
Crush washers, (4) Dorman A5795 $4.20 Local Parts store.

Some of these parts could probably be bought for cheaper depending on sources. I just decided to go with GM parts to start with except for the rotors. We use Raybestos rotors at our shop and they seem to be quality stuff, despite being made in China. What was strange is the the Z06 calipers are painted red and are exactly the same as "regular" C5 calipers but they are a few bucks cheaper

I took the car out for a quick test drive and there was a marked difference in stopping power compared to the old 11.9" rotors and Hawk HPS pads. The Z06 pad is very similar to the HPS pad but the Z06 pad is almost twice the surface area of the early C4 pad and the swept area of the C5 rotor is just huge compared to the early C4 rotor.

Didn't get too much of a chance to do anything but four 60 to 0 stops and that made it seem this was worth the effort and expense. Got a track day coming up next month and I hope it will be even more fun now. That track day will tell me if I really need the DRM brake bias spring.

farscape1a

where are the pics???

sounds awesome!

ffvetteman

Thanks for the post!!

I was just looking into doing the exact same upgrade on my 84 and the info you provided is invaluable!!

I hope to get it done soon, so thanks again for the info.

I would love to see some pictures if you get a chance.

c4cruiser

Upgrading the 84 brakes to C5 stuff may be a issue. The holes for the brackets on the 84 spindle are smaller and there is less material around the holes. Some say that makes for a weaker attachment point given the vast improvement in braking capabilities with C5 brakes.

There may be some folks who have done a C5 upgrade on an 84, but I would check with the vendors that carry the kits (Vette Brakes, Doug Rippie or Lingenfelter) to make sure that the 84 spindles are up to it.

I'll try to get some pics up this coming weekend. When I did the upgrade, the battery in my Nikon D40 was dead.

ffvetteman

Interesting, I thought the 84-87 suspension and brakes were the same design, short of spring rates and shock stifness.

I have not dug into the brakes on my car in a while, hense why I need new brakes, but is the caliper mount removable? Is it possible to use a newer design caliper mount on the 84?

I was going to check with Corvette Sport because they put a set of C5 brakes on my friends 93 Trans Am.

c4cruiser

The brakes and suspension is the same design but the 84 spindle has less "meat" around the holes for the caliper mounting bracket bolts. This effectively makes the spindle weaker in that area when it comes to the increased torque placed on the spindle when C5 brakes are installed up front.

The caliper mounting bracket is removable (the two 21mm bolts you see at the backside of the spindle. But the C5 rotor hat is not as tall as the early C4 rotor hat. Along with the C5 caliper being mounted further out to accommodate the larger diameter 13" rotor (over the stock 11.5" rotor), the custom bracket is a requirement to properly position the C5 caliper.

To mount the C5 caliper, you have to use the C5 caliper mounting bracket as the pads slide into the sides of the bracket. With the C4 pads, they simply sit free until you drop the caliper over them.

jhammons01

Now....since you only did the fronts....you'll have to add a "Brake Bias" adjustment so the back end does not "come around" in turns.

(Don't feed the troll...AKA as me)

c4cruiser

Here's a few pics of the C5 brakes installed on my 87 (dialup, go eat lunch and take a nap )

The pic of the wheel shows the clearance between the top of the caliper and the inside of the wheel rim. Pleez excuse the dirty tire, I just got them mounted on the new wheels. :o

The pics of the caliper and rotor shows that this is a pretty straight forward install in terms of assembly. It's actually no different than replacing rotors with the exception of adding the adapter and using the C5 components.

I slipped the old rotor onto the studs to show the difference between the thickness, diameter, and hat dimensions.

I'll be ordering the DRM spring today.

jhammons01

^^See Picture #2....is that a plate that converts the bolt hole pattern from the C4 to the C5 caliper??

If so....is is Aluminum??? and if so, do you feel comfortable that the C4 caliper bolts are threaded into Aluminum plates? It seems a bit weak if you ask me....I may be wrong in what I am seeing. But I'd feel better if there was a nut on the backside in between the C5 caliper and the adapter plate.

Just tell me I am worrying about nothing...I'm just giving a first thought opinion that is based on no real facts.

c4cruiser

The adapter is made from high-strength steel and is nickle plated. The adapter has two threaded holes just like the caliper abutment bracket. The two Allen bolts have the same thread size as the original bracket bolts and are a metric grade 10.9 just like the OEM bolts.

Both sets of bolts have Loctite blue threadlocker applied and torqued to 133 ft-lbs (factory spec for the 87).

jhammons01

Emily Lattella

"never Mind"

Oh, I do need to add.........Good job, it is inspirational. I'd be after this swap right away if it weren't for the wheels having to be changed.

Calderone

Excellent thread cruiser !
I wonder if my Fikse will clear this because im using a 1.25" spacer on the front.-

rickneworleansla

scorp508

Ugh... you might have just made me spend $650.

88BlackZ-51

Welcome back.

It looks like you stil have the car?

scorp508

Yep! It's been under her cover for almost 3 years now. I bought a house in 2006 and the free time, priorities, and spare money equation changed quite a bit.

93LT1

Great write-up.. thx

383tpimachine

badasss
ill be doing this VERY soon.

are the rotors available in slotted?
I like a lil show with my rotors

c4cruiser

You should be able to find C5 front slotted rotors from a variety of sources. Also drilled/slotted, cyro treated, two-piece, etc. Just depends on how much you want to spend for rotors.

Because my 87 is primarily used for autocross and track days, I just use stock rotors because the replacement costs are low.

TJM

Thanks ! This takes care of a lot of questions I was asking on my thread.

TJM