Looking for recommendations for brake upgrade for my C6 Base. Going to be making significantly more power when I install a new A&A kit and want the car to be able to stop. Probably looking to retain factory calipers. Thanks in advance for opinions.

 

Adding the J55 rotors (standard on Z51) and caliper brackets with the brake pads of your choice is the simplest method of upgrading base brakes and retaining stock calipers. The J55 rotors are approximately 1" larger in diameter giving you a greater sweep area. I just did mine. It took about 3 hours and cost about $400. Nothing difficult.

 

Brakes are only as good as the tires on the car, hence upgrade the brakes to bite better, but do not increase the grip of the tires, and you just get into the ABS system with less pedal push instead.

So on that note, first thing to do is to power flush the brake fluid to get the old humidity contaminated fluid out, and new clean/ dry fluid in to begin with so the pedal is working correctly. Now with the OEM brakes working their best, re-evaluate if you do need to get into better gripping brakes if you are not able to get into the ABS system fast enough, or if the problem is tire grip for increased breaking isntead.

Simply, will bank that it just more initial bite, better pedal feed back, and maybe slightly higher working temps that the OEM base brake pads are not offering now (since you will be able to get into the ABS system fast enough with enough pedal push with clean brake fluid in the system), and that can be solved by just switching to either the OEM HD pads found on the Z51 cars, or going to 1521's that will dust less than the HD pads isntead.

Note, service manual calls out for the Dot 3 brake fluid to be power flushed every three year, and if you are running Dot 4 that collects humidity faster (dot 4 does have a higher temp range through), then may have to power flush more often if you are getting the brake fluid up to those higher working temps. Also, really takes a Tech 2 to power flush the abs pump to get the old fluid out of it at the time of power flushing as well.

 

Great info. Looks like an easy solution. I guess I would just search "C6 Caliper brackets" for that part?

 

Yes good points. I'll make sure to get a correct flush done as part of the job. I'm also planning for new tires as well since I currently have rock hard run flats. Trying to figure out the good tire options for a "spirited driver" that will very rarely if at all see the track.

 

J55 Abutment Brackets (Caliper Brackets)
front brackets #88964166
rear brackets #88964167

GM Z51 Rotors
89060328 Front Brake Rotors
89060329 Rear Brake Rotors

Personally I don't like the GM rotors for a number of reasons. They cost more, they rust and they are not correctly drilled and slotted. I went with Rotors from Brake Motive and they work great. Contain zinc so they don't rust, are drilled and slotted correctly for right and left side, and best of all they are inexpensive.

Brake Motive C6 Z51 Rotors
https://www.ebay.com/itm/Front-Rear-...4AAOSwi1Zd6V9l

If you are going to track the car you probably want to go a different direction as the drilled brake rotors will crack. For spirited street driving or autocross this is an improvement over the base JL9 brakes that doesn't cost much.

If you are doing the work Dano suggests I would also swap my brake lines for stainless steel lines while I was swapping fluids and bleeding brakes. The SS brake lines will cost you another $100.

If nothing else the larger, drilled and slotted, shiny zinc coated rotors look a lot better then the plain and tarnished base JL9 rotors.

YMMV

 

awesome info. I like the look of drilled/slotted as well. Thanks for taking the time...

 

Just to clarify, Z51 is a performance option on '05-'09 base cars, that includes J55 rotors among other things. J55 is the RPO designation for the heavy-duty brakes that are also used on the base '07-'13 cars as part of the F55 mag ride option and also as a stand-alone option on all base C6's.

So if you are looking for rotors and caliper brackets, don't limit yourself to finding "Z51" parts, but look for "J55" parts instead.

 

awesome thanks. Anything specific you reccomend?

 

Not really. I just wanted to clarify the correct nomenclature to avoid confusion. I do recommend using semi-metallic pads if you tend to play hard. It's performance vs appearance.

I personally use the JL9 (aka base) rotors, drilled in the same pattern as J55 rotors. They're lighter and smaller, which makes them better for drag racing as opposed to road racing.

Strangely enough, the OEM J55 rotors don't have correct airflow for cooling. One front has correct rotation and the other is backwards. The rears are worse, since they draw air from the exterior and vent toward the interior right where the cooling duct is trying to force air in from the back side. Yet the JL9 rotors utilize an interior post construction rather than vanes and the unique placement creates proper airflow irrespective of rotation.

If you want the larger J55 size, it makes good sense to ensure the cooling airflow is correct for all 4 wheels.

 

Would I be better served with upgraded Base size rotors and more aggressive pads instead of moving up to j55 size? Any recommends?

 

You could go with these rotors that are drilled and slotted for a base. They look and work great.

https://www.ebay.com/itm/400895030923

Nothing wrong with the ceramic pads that come with the above rotors, low dust and work as good or better then stock... but if you are looking for a serious improvement over stock you might want to look at different pads.

If you don't plan on tracking the car the above is plenty and will look great.

 

Assuming you plan to aggressively use the new power beyond on a dragstrip, yet retain the OEM calipers, I'd suggest the J55 size rotors AND semi-metallic pads. That doesn't mean race pads, but just good quality street pads.

One additional thing to note, and this ties into Dano523's warning about tires, is that the JL9 rear calipers have a slightly larger (45mm) piston than the ones used on the J55 rear calipers (42mm). GM did that to compensate for the 1" larger rear rotors. The front calipers for both JL9 and J55 are identical. Of course, GM didn't plan for a blower on that car either.
Make your tire selection carefully, according to how you intend to use the car.

 

I've been searching for C6 Z51 brake info which led me here before I possibly start a new thread. I recently purchased a 2008 C6 Z51. It came with extensive maintenance records showing that prior owners were religious with all recommended maintenance so I feel that I have a good picture of services completed. The records show the last brake service as getting new rotors and pads installed - the rotors and pads purchased online, installation was done by a shop. In the pictures you can see that the existing pads on the rear brakes are only wearing about 2/3 of the rotor surface which I'm certain is incorrect. The pads aren't even wearing over the inner-most drill holes. I am suspect of the rear brakes and the possibility that maybe "base model" pads were installed rather than larger Z51 pads. Taking a rough measurement through the rim it appears the rear rotors are 330mm which would be correct from info I found on here. From the looks of the caliper brackets it doesn't appear that they could accommodate deeper pads. I'm hoping more experienced eyes on this forum can help me determine. I guess the calipers could've been changed although there's no records for it. It's hard to believe smaller calipers would've ever been installed. The front brakes are using the full rotor surface and every other car I have uses the full rotor surface so I'm pretty sure something is wrong here. Let me know what you guys see and think. If someone has a pic of correct C6 Z51 rear brakes, please post. Thank you in advance for any advice and info.

 

The base C6 and Z51 take the same pad shape

 

What you see is by design. Not all of the rotor surface is swept by the pad.

 

Before you start doing anything, confirm that the car actually has the Z51 option. Look on the glovebox lid for the 3 character RPO code Z51. If Z51 is there, that option includes the J55 brakes, since J55 is the code for the brakes the factory installed. JL9 is for base brakes, so if that's listed, you won't find the Z51 code. I mention this because lots of C6 owners have swapped out the original OEM brakes for something else.

Assuming you find both the Z51 and J55 codes, I can assure you the rotors you show in the photos are not OEM rotors. The width of the swept area by the pads appears to be correct, but OEM J55 rotors only have 2 rows of holes and the countersinks are not that deep. The physical size of the JL9 and J55 pads are identical, but the pad materials are different.

To avoid any future confusion, remember that Z51 is simply an option and not a model.

 

Yeah, but not GM's design.

 

Great info HOXXOH. Among the 58 3-digit codes, J55 & Z51 are listed. The rotors are definitely aftermarket, the service history/paperwork that came with the car shows these rotors coming from "Drilledrotors.com".

It seems my only issue is that the rotor wear looks strange - and maybe that's just me. Brake function seems fine, I had it out on track this past weekend and even tried the ABS function a few times at 60 mph and all seemed fine. I'll plan to run these down and then replace.

I've noticed when shopping for brake pads such as Carbotech, Hawk, etc, there are listings for C6 base and a separate listing for C6 Z51. I don't recall which websites I was looking at but this made me think there was a physical difference.

While on the topic, is there a preferred brand of pad for track duty? I've seen a lot of mention of Carbotech XP10 & 8's. Do these squeal too much for occasional normal driving? Preferred pad vendor? I see KNS brakes on this forum and their prices seem fair with the comparing I've done. When replacing the rotors, do you recommend vented & drilled or vented only. Any particular rotor brand or vendor for quality & price?

I appreciate the info, my mind is at ease knowing what I've got here. Thanks again.

 

A little history here. When the C6 was introduced in '05 with just one model, the aftermarket quickly created their catalogs to reflect any differences in parts. Since there were 2 different brake sizes, they used the Z51 code (an option that included gearing, suspension, cooling, tires, brakes, etc) to define rotor size and pad material. That worked even in '06 when the Z06 was a different model and '09 with the ZR1. However, GM dropped the Z51 option in '10. What caused confusion was that GM also offered the J55 brakes as stand-alone option called "Heavy duty brakes" starting in '05 and included them as part of the F55 option (the mag ride suspension option) starting in '07. The aftermarket didn't change their catalogs quickly or at all, which left John Q Public believing that J55 brakes were actually named Z51 brakes.

Some things to consider when you get to the point of needing replacements. How much track time are you doing in relation to daily driving and which is more important to you. If track time wins that question, there are several options to improve upon the current setup with prices to match. Play with what you have, so you'll have a better idea of what you might need.