rrt898

I wanted some input from people who have upgraded their brakes?? Is the J55 worth it or should I go with a more expensive brake upgrade? I have a 1986 automatic coupe.

thanks......

rodj

What is your driving style / car usage ?
Street / track / strip ?
Budget?

J55 are better than stock 12" but are now a more expensive conversion than even more superior C5 brakes
BUT they require 17" rims to clear the calipers

cv67

For most driving, no imo.
If its going to see a lot of track use maybe aftermarket. Some like the C5 stuff

theforthstooge

I did mine a couple of months ago for not much money and I like the improvement. Also have braided steel brake lines and Hawk HPS pads. Got the parts at corvette recycling. About 80 each for calipers and brackets and NOS rotors for 20 each. The calipers looked brand new and had NOS pads in there too. Ran those for a while but the Hawk pads have more bite. Here's the parts: http://www.corvetterecycling.com/category_s/214.htm

Cliff Harris

I put J55 brakes on my '86. I heard somewhere that it adds about 20% to the braking performance.

You do need custom caliper brackets because the '88 and newer caliper bracket holes are farther apart than the older cars. Mine came from Stainless Steel Brake Co. I bought a kit from Corvette Central that had everything in it. That included cheapo brake hoses that failed after a few years (they looked like a balloon wiener dog).

I do have a problem with the calipers scraping the inside of the stock 16" Z51 wheels once in a while (the wheels DO bend!). I heard that there are no aftermarket 16" wheels that will clear. 17" wheels fix that problem.

gerardvg

Hi
I converted my 85 vette to the 88-96 performance option J55 13 inch rotors and calipers a few years back and used the hawk brake pads. I found the disc's,calipers and adapter brackets on ebay for $190. (nice to win a bargain) The hawk pads bite heaps better than standard but the discs wear more quickly so expect 3 pad changes per disc change, more friction means better bite and brake performance.

I also installed an adjustable brake bias valve to prevent the rear brakes locking before the front with the standard master cylinder. (the later master cylinder with correct proportioning spring did not have the lower brake line fitting). Although your 86 has anti lock brakes you will need an adjustable brake bias valve, (under the car within easy reach but up out of harms way) and adjust to prevent the abs kicking in when your rear wheels start to lock well before the front brakes are even starting to bite. otherwise you would severely limit your overall brake performance.You will need to pull your ABS fuse to set it up so the front lock first just before the rear never rear only then can refit the ABS fuse

You will most likely need 17 inch rims and the 13'' disc's really fill 17" A mold wheels nicely ( i had the 17 inch rims on years before the brake upgrade)

This combination have lasted several track days, (the standard pads disintegrated when they got hot). The Hawk pads are great however more black brake dust on your wheels, but you can be guaranteed the brake pedal does not go to the floor after a few fast laps.
Go for it you won't regret it.

c4cruiser

There are a number of good brake pads available that will improve braking performance over stock. Also replace the flex hoses with stainless flex lines and add new rotors. You didn't say what you are after in terms of performance but a simple pad change to a good performance pad will be a noticeable difference. Don't forget to do a complete flush of the brake fluid

Going to the J55 brakes or a C5 front brake upgrade will be a big improvement over stock, but expect to pay around $650 for all new parts. The custom adapters for either the J55 or the C5 brakes may be hard to find but with a bit of searching they are out there. I would recommend the C5 conversion as the rotors are thicker, there are a wide variety of pads for C5 brakes, and the caliper pistons are larger.

I did a C5 front brake conversion on my '87 and it was easy to do. I bought new C5 Z06 calipers, Z06-specific pads, stock-style C5 rotors, fresh DOT4 fluid, and I was even able to use the existing brake hoses. I already had a set of ZR-1 style 17x9.5" wheels with the specific 84-87 38mm offset. You will need the 17" wheels for a C5 brake conversion. Try that online auction site for AFS Wheels by searching there for "Corvette AFS Wheels".

There are a wide variety of 275/40-17 tires available at good prices. The nice thing about this particular size is that when mounted, it is almost the same size as the OEM 255/50-16 tire so it won't change the speedo readout.

An adjustable bias valve is a good idea for the 85. Your 85 doesn't have ABS so having the ability to manually adjust the brake bias would be a help. That requires some brake line modification to install the valve. But Doug Rippie Motorsports has a brake bias spring made for non-ABS C4's that takes all of 5 minutes to install without removing the master cylinder. I paid $20 for one for my '87 delivered to my house.

PLRX

All upgrades are worth it. If your Vette is for a city drive or weekends your OEM set up with high performance pads will be ok.

If you would like more brake performance the J55 will provide it for you. There was a reason it was a ZR1 option from 90 to 94 and then standard for 95 and 96 on all Vettes.

You can buy an used J55 set up cheap these days.

Rob31

I dissagree . YOU DO NOT NEED AN ADJUSTABLE PROPORTIONING VALVE with ABS
I converted my 86 to J55 s I have never had a rear brake lock up problem . And I track the snot out of mine .
I also have the Rippie spring , still no rear problem .
Its a Good upgrade if you track the car . You could get by with good pads /lines on a DD. Same pad for a single puck and a J55
17 inch wheels

GREGGPENN

IIRC, brakes increased 1" when they converted to 17" wheels in 88-89. If the J55 option is better than that, does that mean we're talking about:
11" brakes - earliest years
12" brakes - 88-94
13" brakes - ZR1, 95-96

I assume I'd need to stay with the 12" setup unless I change calipers.

Please clarify as I'm ready to buy new front rotors and pads. I'm also considering slotted/drilled...thinking I needed 12" rotors/pads.

Also, if there's room for 13" (J55) brakes on 17" wheels, does that mean you can get 2" more brake with 1" larger wheels? Don't quite get this....

desertmike1

1/2" more brake disc per side; = 1" overall, [diameter]

12" rotor/2= 6.0" on center
13" rotor/2= 6.5" on center

GREGGPENN

1" larger wheels are also 1/2" larger radius.

desertmike1

which makes me kind of currious about what kind of clearance I have with my J55's and 17" rims from the factory...

Black89Z51

Only go with drilled rotors if you're trying to showboat. They aren't worth a crap for track duty. They crack when they get hot.

trackbird

More than you think. I'm parting out my '92 Z28 road race car and I had J55 brakes on the Camaro. The J55 13" brakes will actually fit (it's tight, but they don't rub) under 16" factory IROC wheels (somewhere I have pics). I ran those brakes on the Camaro at Nashville Super Speedway on the road course and the braking zone into turn one was roughly 125 mph to 25 mph. I ran them for 30 minute sessions and didn't have any issues with them (using a Hawk HP+ pad, no brake ducts and street tires, I was shaking down a new car at the time).

I sold the spindles and kept the calipers, rotors and brackets (which turned out to have 10mm bolts in them so I found a set of J55 brackets) and put them on my '91 Corvette. It's a nice improvement and a much better set of brakes than the 12" (if you need that much brake). Since I had the parts, it was a no brainer to do the swap. I'd do it again (for what I have invested in it and the parts I already had).

1991Z07

The J55's were standard on ALL Z07 cars, as well as the Challenge cars (for which they were originally developed).

Eventually, they just made them standard...don't know if they ran out of the "original" 12" versions and had more 13" J55's in inventory or what, but when anyone wanted to track or autocross in the 90's...J55's were the only option you had. Thankfully, they (eventually) would let update/backdate happen and anyone could run them in NCCC. I think SCCA is still in the dark ages on it though...if it didn't come on YOUR car you can't use it (at least the last time I bothered to read the rulebook).

I run 18" wheels on my Z07...got plenty of room for a larger rotor/caliper. If it wasn't for the bulk of the C6Z06 calipers I could bolt them up...but they won't clear the spokes of the wheels.

An upgrade there means new wheels as well.

jsinga

It looks like you already have 17" wheels from the pic.
If that's the case go the C5 upgrade route.
Reasons:
C5 calipers are all the same. Easy to find used cheap
C5 rotors are thicker AND a lot cheaper than J55 rotors
You still need custom adapter brackets
Pads are a wash price wise
You end up with more brake.

I have the J55 upgrade on my 87. Totally worth it.
The fit under the 16x9.5" wheels. I had to file some off the tops of the calipers to keep them from scraping the inside of the wheel.
Cost me under $500. The special caliper brackets for early cars are at Corvette Central I remember they were a little over $100 each.
Got used calipers.
Carbotech had a deal on rotors and pads. I was on the road and picked them up in NC and didn't pay shipping.
I have Carbotech Bobcat pads. They don't eat rotors, stop good hot or cold and make very little brake dust and never squeal. They are a steet, maybe autocross pad.

JS

mcm95403

Great info on the Carbotech pads, thanks!

Adam@Amp'dAutosport.com

Let me know if I can help you out

GREGGPENN

I ended up ordering stock replacement parts today. Stayed away from the drilled/slotted stuff since feedback in other threads left me disappointed.

I got Wagner BD61842 rotors and Bendix D412CT Ceramic pads. Ceramic seemed to get the best feedback for stopping and dust. We'll see....

Thanks for the feedback. Probably should've gone with larger brakes but wanted to see what new ones would do first -- plus keep the swap price-friendly.