NASAblue

So, I've been considering a brake upgrade on a 97 C5:

Here's what I have through 8 seasons of HPDE and Instruction
-SS brake lines (8yrs old, do they wear out?)
-C6 Z51 calipers (bigger pistons?)
-DBA 5000 front slotted rotors (3 pair) 2 need replacement rings are out of this world expensive so I'm thinking it's a good time for an upgrade
-2 sets of stock C5 Z06 wheels and Hoosiers
-Hawk HT 10 or DTC 70F/60R (I actually prefer HT10)
-super blue fluid (changed and bled at nausea)
-Front brake cooling duct extension and spindle ducts

Symptoms:
-Totally inconsistent brake pedal; IT SUCKS!!!!!!!!!!
-After bleeding, I might have 2 turns with a good pedal before it goes to the above condition
-longer lighter brakes due to brakes locking up fairly easily (abs went kaput years ago, constant source of frustration)
-I spend FOREVER braking, I can't get a good hard brake to scrub speed concisely and light taps or left foot stabs to rotate/set the car are near impossible due to the pedal travel
-also the car seems to want to rotate and rear wants to come forward under braking (sounds like a suspension issue from other posts)

Options:
-LG G2 wilwood kit would be perfect to run my stock rims and tires I already have ~$1500
-Better BBK like AP or stoptech sell wheels and tires get new wheels ~$6000 if I'm lucky

To those with a G2 kit, Was it a vast improvement over the stock caliper. Some on here say "o the stock caliper is great and the G2 is not worth it as is only a slight upgrade." Is this true, is the G2 kit only a marginal increase in brake feel and maybe not worth going from stock 2 pistons to the SL6?

I.E. some say stock rotors are fine, but I was cracking a set of those a weekend if not per day at the track. After upgrading to the 2 piece, I change a set a season and they are much better. Is the G2 kit the same thing as the rotors, poo pooed by everyone who doesn’t have them, but once you do there's no looking back?

Thanks for your thoughts and suggestions

Bill Dearborn

Your inconsistent pedal is due to pad taper not boiling the fluid. Boiling results in a soft/spongy pedal while taper results in long pedal travel. This happens all the time with the C5 or C6 base/Z51 brake calipers. To get a consistent pedal you need to tap the brake pedal with your left foot a couple of times while approaching the braking zone. Then when it is time to brake you take your right foot off the gas and use it to brake. Flip your pads from one side of the car to the other to compensate for the taper and that will reduce the pedal travel.

If you want a big brake kit for the front look at the LG G Stop Kit. It uses the Wilwood LS6 wide caliper, fits under the stock C5Z06 front wheel, uses the C5 front rotor and uses a very thick brake pad (7420). Brake pad cost difference over several years will pay for the upgrade. If you are using C5Z rear wheels you will have to use an 1/8 in spacer to make sure the wheels don't hit the calipers under hard cornering. Without the spacer they clear the caliper by 1/16 on an inch.

I ran the G Stop kit on my C5Z for 4 years and it was great. The caliper isn't as sensitive to the taper issue so you don't get the long pedal. I had consistent pedal every time I went to the brakes. The pads taper so you do need to flip them from one side of the car to the other to compensate for the wear but you do that more to extend pad life than anything else. It is also a good idea to use pad spacers to keep the pistons from extending too far when the pads get a lot of wear on them. Use thick spacers (basically pad backing plates) along with Titanium or Phenolic heat shields. I got my spacers and heat shields from Behling Racing Equipment in Wisconsin. Since they were for a slightly different pad I had to grind off a raised section of the backing plates used for the locating pin and make it a slot instead but that was all the customization it took. http://www.behlingracing.com/assets/...2%2097-117.pdf

Bill

JeremyGSU

I agree with Bill on pad taper and I recommend SKF front hubs if you want to keep the stock calipers. I had a terrible time with inconsistent pedal on the stock calipers but once I installed those the pedal was firm throughout the track day. No more fade. I would also recommend a stronger brake fluid.

kmagvette

but will go one step further...get the SKF hubs if you want to track the car, especially with slicks. Aside from much stronger flanges, the bearing themselves remain on-axis much better than stock or, even worse, cheeseball Timkin replacements.

You need to flip your pads as Bill suggests to manage taper, plenty of other threads on that

You will still get a slightly longer pedal if you run your pads to the rivets as I do. Brake fluid selection is almost as contentious as oil selection is around here. I find that Motul RBF600 does the trick at about $17/pt if you buy it by the case. I am sure there are plenty of other quality fluids to choose from.

Scooter70

Did you remove the ABS block and replace the lines or is it still plumbed into the system? There could be air trapped in there with no way to escape since the ABS pump isn't functioning.

Cobra4B

I agree that SKFs are better, but Timken is the OEM supplier. The bearing you get at VatoZone is the same one you get at the dealer w/o the dealer markup.

CHJ In Virginia

Spend a few $ and get the SKF race hubs and the LG Wilwood kit. You will be amazed at the difference in braking capability and pedal stability. I am very happy with the performance of mine !

NASAblue

Bill, thank you. That is exactly the information and experience I was looking for.

Scooter, everything is left as stock 97. The TCS/ABS seems to shut off ramdomly, but consistently on the track to the point where I know I'm not going to have it after the third turn. I've cleaned every contact and ground, hard wired and soldered the wheel speed sensor, put heat protection all over the exhaust and (seperately) the ABS distributin block and EBCM at the BACK of the car.

Would you suggest removing this abs distribution block and coupling the lines? I'm to the point where it would probably feel pretty good to take that thing off it

NASAblue

Thanks for the heads up on the wheel bearings. Though changed recently, I got some wheel bearing assemblies that were supposed to be gm high performance, but I don't have any real assurance that is what they are.

It would make sense to change those no matter what as well.

Thank you all for you help, keep any ideas/insight coming.

sperkins

All my brake issues disappeared when I went to SKF's.

NASAblue

Did you put the front calipers in the rear and/or add a new master cylinder with adjustable bias?

Thank you!

CHJ In Virginia

Negative - running stock C5 rear calipers with Wilwood H pads in the rear. F/R balance is fine not requiring a new MC or adjustable bias.

JRitt@essex

NASABlue,
Take a long hard look at our system before making a decision. We've had many, many customers in the same boat as you. Now they all say they've totally forgotten about brakes and just drive their car. We have everyone from total newbs to national race winners running our system.

Our system is built around AP Racing components. The system is extremely stout, and most of our customers are getting at least a season out of discs. Replacement discs are cheap when you do need them, and replacement pads are very cheap and readily available as well. They will fit OEM C5Z06 wheels, so you don't need to buy new wheels and tires, or spend $6,000.

Take a read of this thread and feel free to contact me with any questions. I don't think you'll find a bigger bang for the buck solution. Thanks.

http://forums.corvetteforum.com/auto...brake-kit.html


Here are your issues:
Symptoms:
-Totally inconsistent brake pedal; IT SUCKS!!!!!!!!!!
Not a problem with our system. Most customers never have any pedal issues, and run all day without any noticeable change in pedal.

-After bleeding, I might have 2 turns with a good pedal before it goes to the above condition
Most of our customers almost never have to bleed before sessions. In fact, I can't name one who does so on a regular basis. it becomes a non-issue, and you spend your day driving and having fun, not wrenching on brakes.

-longer lighter brakes due to brakes locking up fairly easily (abs went kaput years ago, constant source of frustration)
Our system is designed with the proper piston sizing in mind to mate with the OEM master cylinder. They bolt on and seamlessly integrate with ABS. No lock-ups, or odd ABS activity. They also work great without ABS because they are sized properly.

-I spend FOREVER braking, I can't get a good hard brake to scrub speed concisely and light taps or left foot stabs to rotate/set the car are near impossible due to the pedal travel
No pedal travel issues, and hard braking events will no longer be a thing to fear.

-also the car seems to want to rotate and rear wants to come forward under braking (sounds like a suspension issue from other posts)
This could be suspension, or a brake bias issue. Too much rear brake can make things squirrely.

Okay...that all probably sounds too good to be true. It is not. Just check out that thread, and this one:
http://forums.corvetteforum.com/auto...ease-read.html

All of our customers say the same thing..."I wish I had bought this kit a long time ago!" Buy it, then send me a Christmas card thanking me for how much more fun your days at the track become.

Product details on our site:http://www.essexparts.com/shop/compe...corvettes.html

Bill Dearborn

You are experiencing a problem that existed in the original 97 EBCM. There was a design error that caused a phase lock loop that locked onto input signals to fail under certain conditions. Mostly racers and autocrossers experienced the problem. I flatspotted several tires due to the problem. Having a source that knew the people involved in developing the EBCM I found out they were releasing a new design EBCM to address the problem. That was in early 98 but it didn't show up in the GM supply line until late 99. I alerted the dealer that I wanted the new module and it was replaced under factory warranty and that ended my problems.

The 98, 99 and 00 cars had similar on track issues with their EBCMs where bumpy pavement would cause the erratic wheel speed sensor signals that would shut the system down. This usually happened when the brakes weren't being applied. The solution to those issues was to mount a toggle switch on the dash within easy reach of the driver. That switch controlled a relay that was placed in line with the 12V power going to the module. When the system failed the driver would reach over and toggle the switch to cut off the power. The EBCM would reset like it does on engine start and everything worked again. You could do something similar with your EBCM and when it fails at the third turn you reach over and toggle the power and reset the EBCM.

To give credit where it is due I first saw this implemented on Danny Kellermeyer's 99 C5 racecars. When I asked what the switch was he told me. The switch is on the car shown in this link http://www.djrace.com/index.html . If you send him an email he may provide more info on what he did.

Bill

NASAblue

Bill, I can't believe it! This explains so much. I have often thought of retrofitting my car with a later C5 module locating it in the rear position, but mounting a switch is a solid option. I often have to disconnect the harness in order to reset the EBCM, so that makes sense.

I'm just about to relocate the battery, so it would be easy to run the wire at the same time.

I can't believe it!!!!!!!!!!

NASAblue

thank you JRitt The AP looks like a good system too.