How do I tell if I have JL9 or J55 brakes?
05-08-2012, 03:50 PM
#1
Racer
Thread Starter
How do I tell if I have JL9 or J55 brakes?
Went to change the brake pads today and found out I need to work on the calipers. I guess HPDE's and 47k has taking a toll on my boots and seals.
I have a C6/A6 base coupe non-Z51. How do I tell if I have JL9 or J55 calipers. I want to buy a set of OEM calipers.
I'm going to keep the old set of calipers and rebuild them myself and keep them for backups. I plan on doing more HPDE's.
Thanks for any help I can get.
I have a C6/A6 base coupe non-Z51. How do I tell if I have JL9 or J55 calipers. I want to buy a set of OEM calipers.
I'm going to keep the old set of calipers and rebuild them myself and keep them for backups. I plan on doing more HPDE's.
Thanks for any help I can get.
05-08-2012, 04:36 PM
#2
Tech Contributor
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Just check on the RPO Sticker stuck on the Glove Box door. The correct option will be listed. It is listed in alphabetical order.
Bill
Bill
05-08-2012, 04:50 PM
#3
Racer
Thread Starter
They also said the transmission oil pan is missing a bolt. He said it's a special type of bolt that he has to order there nonstock.I should get the car back late Wednesday or early Thursday.
05-08-2012, 09:06 PM
#4
Race Director
Unless somebody has changed the brakes on the car, then your base non Z51 has the JL9 brakes. If you have the OE rotors, they are solid.
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
- JL9 - Front 325mm/12.8"; Rear 305mm/12"
- J55 - Front 340mm/13.4"; Rear 330mm/13"
- J56 - Front 355mm/14"; Rear 340mm/13.4"
- J57 - Front 394mm/15.5"; Rear 380mm/15"
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
Last edited by BEZ06; 05-08-2012 at 09:28 PM.
05-09-2012, 10:14 AM
#5
Racer
Thread Starter
Unless somebody has changed the brakes on the car, then your base non Z51 has the JL9 brakes. If you have the OE rotors, they are solid.
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
- JL9 - Front 325mm/12.8"; Rear 305mm/12"
- J55 - Front 340mm/13.4"; Rear 330mm/13"
- J56 - Front 355mm/14"; Rear 340mm/13.4"
- J57 - Front 394mm/15.5"; Rear 380mm/15"
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
Your info confirmed what I saw on Centric's website. I think the rears have a 42mm piston on J55 for Z51 and 45mm on JL9 for non Z51. The fronts have the same size pistons and connections just a different bracket. I have solid rotors no holes or slots.
I have a set of rotors waiting to go on my car I bought them from KNS. Centric solids 12.8" up front and DBA 4000 slotted for the back.
I have a brake duct kit with 3" hose and spindel duct I got from LAMBERT. I hope to get this installed before my next HPDE.
07-23-2023, 01:51 AM
#6
Unless somebody has changed the brakes on the car, then your base non Z51 has the JL9 brakes. If you have the OE rotors, they are solid.
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
The J55 brakes are on the Z51 and later model year F55's, and the OE rotors are drilled on those cars.
The J56 brakes are the Z06 and GS brakes.
The J57 is the carbon ceramic brake package on the ZR1 and Z07 Z06.
If you don't have your car you can't measure the rotors until you get it back, but when you measure the diameter you can tell what you've got:
- JL9 - Front 325mm/12.8"; Rear 305mm/12"
- J55 - Front 340mm/13.4"; Rear 330mm/13"
- J56 - Front 355mm/14"; Rear 340mm/13.4"
- J57 - Front 394mm/15.5"; Rear 380mm/15"
As far as getting new calipers, the front calipers are exactly the same for both the JL9 and J55. The rear calipers of the J55 on a Z51 have slightly smaller pistons than a rear JL9 caliper in order to maintain the correct front/rear bias with the slightly larger rotors of the Z51.
In actuality, it really doesn't matter which caliper you run on the rear, especially if you're not tracking the car. The EBCM and BPMV have what's called DRP (Dynamic Rear Proportioning) on the earlier C6's, and in about 2009 they changed from a Delphi ABS to a Bosch system and started calling it EBD (Electronic Brake Distribution). In either case, the ABS system's EBCM will take care of front/rear bias for you regardless of which rear caliper you mount on the rear.
The JL9 and J55 calipers are the same size (except for the rear pistons) and will bolt right onto your brackets/suspension members. If you want put the larger Z51 rotors on your car, you'll just need to get the Z51 brackets that will position the calipers out to fit over the larger diameter rotors.
So.....if your rotors are OE and they are solid - you've got JL9 brakes.
There's only a very minor difference in the rear calipers, and either ones will fit on your car. For that matter, I believe any C5 calipers should fit on your car as well.
Just MHO, YMMV!!!
Bob
Can I replace the rotors with JL9 ones (smaller in diameters) and keep the same brake calipers?
tnx in advance.
