J55 brakes
Safety Car
Joined: Apr 2011
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First you will need 17" wheels and possibly spacers depending on the wheel.. You also have to have the bigger rotors.
THEN you can look at adaptor brackets, abutment brackets, calipers, all the new bolts and hardware.
After that $1000 worth of stuff...get yourself some stainless steel lines for all corners or the works been wasted. Last, a new master cyl (w/booster $350) because the old one does not move enough fluid to compensate for the MUCH larger caliper piston space in the C5 brake calipers with dual pistons (Z06) or J55. Many folks complain of a brake pedal that is lower and runs out of travel before good stopping power comes up. It just takes moving more oil to the bigger caliper. It is worth doing though,...its just not simple as bolting the new calipers on.
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
I have J55's on my Z51. They aren't anything to brag about. I would just invest in the best pads you can find and turn or replace your rotors. Also stainless braided lines will help as well.
Le Mans Master
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From: Australia
Instructor
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From: Littleton CO
--Calvin
Safety Car
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Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
In 10 years , never seen anyone with Enkeis state they can't fit a J55 caliper
And the supply of aftermarket 17" rims with correct offset for early cars is limited and not everyone wants to run adapters
And the supply of aftermarket 17" rims with correct offset for early cars is limited and not everyone wants to run adapters
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
I have fitted ZR1 13 inch front disc rotors and twin piston calipers
with adapters. You can use the early master cylinder,
You will need an adjustable brake proportioning valve to stop the rear wheels locking up. Or change your bias spring in the master cylinder.
The 88-96 master cylinder i purchased for the job did not fit as the 85 had a extra brake line port.
I set my adjustable brake proportioning valve and all is good,
I already had the 17 inch A mold wheels on my car before the brake upgrade.
with adapters. You can use the early master cylinder,
You will need an adjustable brake proportioning valve to stop the rear wheels locking up. Or change your bias spring in the master cylinder.
The 88-96 master cylinder i purchased for the job did not fit as the 85 had a extra brake line port.
I set my adjustable brake proportioning valve and all is good,
I already had the 17 inch A mold wheels on my car before the brake upgrade.
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Pro
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From: Yukon OK
I did this a number of years ago. Here is what I found out:
1. I used some 17" A mold wheels with the proper offset. The stock wheels would not work. Not sure what others might work.
2. The brake caliper has to move outward to allow for the larger diameter rotor. It also has to move laterally because the rotor is also thicker. This is complicated by the larger caliper size needing to rotate slightly.
3. You must replace both the rotor and the calipers.
After having done this mod I would advise against it unless you can get the caliper / rotors REALLY cheap. Better to go with an upgrade package that will just bolt on. The stock 85 brakes are really weak. Going to the J55 plus a 9.5" front tire was a huge improvment.
Look at my Flickr account. I show the brackets I machined to do the job and some pics on how I did it.
http://www.flickr.com/photos/1757654...7602879432548/
There are some adapter brackets you can buy to do this but it adds about $200 to the cost of the project.
1. I used some 17" A mold wheels with the proper offset. The stock wheels would not work. Not sure what others might work.
2. The brake caliper has to move outward to allow for the larger diameter rotor. It also has to move laterally because the rotor is also thicker. This is complicated by the larger caliper size needing to rotate slightly.
3. You must replace both the rotor and the calipers.
After having done this mod I would advise against it unless you can get the caliper / rotors REALLY cheap. Better to go with an upgrade package that will just bolt on. The stock 85 brakes are really weak. Going to the J55 plus a 9.5" front tire was a huge improvment.
Look at my Flickr account. I show the brackets I machined to do the job and some pics on how I did it.
http://www.flickr.com/photos/1757654...7602879432548/
There are some adapter brackets you can buy to do this but it adds about $200 to the cost of the project.
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
I got my ZR1 brake disc's calipers and adapters for $190 on ebay Australia a few years back 
Like new discs and calipers
Well we can be lucky some times, people did not notice they were the 13 inch brakes
I snapped them up pretty quick smart
Like new discs and calipersWell we can be lucky some times, people did not notice they were the 13 inch brakes
I snapped them up pretty quick smart
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
In 10 years , never seen anyone with Enkeis state they can't fit a J55 caliper
You're right....I was refering to the larger ZO6 caliper. I can't slip a sheet of paper between my caliper and rim.Without spacer/adaptors the wheel was nowhere close to fitting over the new brakes.
And the supply of aftermarket 17" rims with correct offset for early cars is limited and not everyone wants to run adapters
You're right....I was refering to the larger ZO6 caliper. I can't slip a sheet of paper between my caliper and rim.Without spacer/adaptors the wheel was nowhere close to fitting over the new brakes.
And the supply of aftermarket 17" rims with correct offset for early cars is limited and not everyone wants to run adapters
Last edited by leesvet; Jul 19, 2011 at 08:34 PM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
I think its the spoke ZR copies that I see ready to roll...Like I was saying elsewhere, I thought it was a law that they make no other wheel than the 5 spoke of some sort.. and seems like everyone wants to have ZR1 wheels..persoanlly, I am not a fan of the spoke.
