My brakes suck!
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Heel & Toe
Joined: Jul 2011
Posts: 24
Likes: 0
From: Palatka FL
My brakes suck!
I have new pads new braided lines new rotors no leaks good vacuum and crap for brakes I was going to my first autocross Sunday but rethinking it till I resolve the brake issue. Its a c4 84.Anyone with ideas?
Safety Car
Joined: Dec 2009
Posts: 4,363
Likes: 429
From: Birmingham Al
Most C-4 brakes ,I think are not very good.. Start looking for better ,,I don't know witch ones are better the guys on here know more that I do about that ..I just have C-5 on my front and way better.. Lot's to think about what you going to do with the vett,race driver ?? Good luck
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
the brakes on my 85 were very good, as well as my present 96, but the brakes on my 90, at best, were terrible. i went through everything - new master cylinder, d/s rotors, upgraded pads, SS brake lines, etc. nothing would help. it was damn near impossible to get the ABS to kick in. took it into the dealer to see if they could find anything wrong - they said no - everything was fine. i would have hated to be in a "panic stop" situation with that car - would have killed somebody or myself...
Burning Brakes
Joined: Nov 2008
Posts: 995
Likes: 1
From: Naples Campania
I bought an oversized brake booster and it helped on the 91. There was a thread a little while ago that was talking about the ABS acting up. They did kind of a reset by going out when the road was wet and doing and long hard stomp on the brake. I guess it forced the ABS computer to re-think itself and helped a lot.
If you get a new system, go all out. These things are kinda heavy. I'm looking for a 6 piston system, I'll let you know if I find anything
If you get a new system, go all out. These things are kinda heavy. I'm looking for a 6 piston system, I'll let you know if I find anything
Safety Car
Joined: Dec 2009
Posts: 4,363
Likes: 429
From: Birmingham Al
The brakes on my 95 very good just better pads stanless lines work great..My 96 have to hit a tree to get it to stop tryed to rebuild the hole brake Sys.. Wast of money put C-5 brakes on works fine..Some work, some don't??
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
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St. Jude Donor '12
Most C-4 brakes ,I think are not very good.. Start looking for better ,,I don't know witch ones are better the guys on here know more that I do about that ..I just have C-5 on my front and way better.. Lot's to think about what you going to do with the vett,race driver ?? Good luck
OP and anyone else - the C4 JL9 brakes are adequate for Autocross, and HPDE - You just need a well working system and good pads.
The J55 brakes are as capeable as C5 brakes. Sometimes I can out brake them, sometimes not. Again a well working system and race pads are needed.
So lets dig into the problem. An 84 is what 27 / 28 years old?
So seals in the brake pistons and master cylinder have been subjected to lack of maintenance. I garuntee you the brake fluid has not been changed the 14 times it should have been. I had an 88 with JL9 brakes and it never had its fluid changed until I did it. The car was 16 years old when I changed the fluid. I initially emptied the master, filled it with fresh fluid and drove it for a week. Every couple of days I changed the fluid in the master cylinder because the old fluid looked like WORMS as it migrated to the master. Changed the pads to Performace Friction Z, took the car to Beaver Run for my first HPDE. The ONLY time I had an issue with the brakes when I as a newbie overheated the pads and had severe fade going into turn 1. Bleed the brakes in the paddock and WENT BACK OUT! Those brakes were adequate!
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
Re inafective early brakes stopping issues
Hi guys
Re brakes not being effective i had the same with my 85 vette, you could stand on the brakes and was unable to lock the brakes.
Lucky for me i bumped into some one who designed the brakes for the early c4 vettes, he said they are meant to be a high metal content brake pad. If you don't have friction the brakes wont work effectively,
I got high metal content brake pads and when i stepped on the brakes i almost went thu the windshield.
So if your disc's don't need to be replaced after 3 brake pad changes your brake pads are inadequate
I can now do as many laps on a race track as i want without brake issues. I did run cooling hoses to the disc's though.
Have since gone to the ZR1 13 inch disks and twin spot calipers, mainly due to the old 12 inch discs looking so tiny with the A mold wheels.
They are a lot better with heat soak but you can make early C4 vettes perform great under braking with the high metal content brake pads.
Disc's and pads are cheap compared to a bumper or hood
Cheers
Gerard
Re brakes not being effective i had the same with my 85 vette, you could stand on the brakes and was unable to lock the brakes.
Lucky for me i bumped into some one who designed the brakes for the early c4 vettes, he said they are meant to be a high metal content brake pad. If you don't have friction the brakes wont work effectively,
I got high metal content brake pads and when i stepped on the brakes i almost went thu the windshield.
So if your disc's don't need to be replaced after 3 brake pad changes your brake pads are inadequate
I can now do as many laps on a race track as i want without brake issues. I did run cooling hoses to the disc's though.
Have since gone to the ZR1 13 inch disks and twin spot calipers, mainly due to the old 12 inch discs looking so tiny with the A mold wheels.
They are a lot better with heat soak but you can make early C4 vettes perform great under braking with the high metal content brake pads.Disc's and pads are cheap compared to a bumper or hood
Cheers
Gerard
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Drifting
Joined: Oct 2005
Posts: 1,916
Likes: 48
From: Angier nc
My brakes suck at any other spped than normal driving.Throw any kind of speed at them and high effort and no stopping power.Kind of reminded me of my 72 nova with drum brakes F&R.
I bought it in 05 and have never touched the rotor or pads.I have replaced the fluid lines and brake fluid.
Now that it can build speed rather quickly I wanted to be able to stop quickly as well.
I replaced all 4 rotors and pads.Performance friction carbon metallic in front and ceramic in the rear.Break in process complete.I fully expect it to stop next time I go on a speed run.
I bought it in 05 and have never touched the rotor or pads.I have replaced the fluid lines and brake fluid.
Now that it can build speed rather quickly I wanted to be able to stop quickly as well.
I replaced all 4 rotors and pads.Performance friction carbon metallic in front and ceramic in the rear.Break in process complete.I fully expect it to stop next time I go on a speed run.
Burning Brakes
Joined: Feb 2006
Posts: 1,177
Likes: 0
From: VALENCIA PA
im a master of late braking c4 brakes suck, period! get yourself a set of c5 calipers (junkyard even) get the brackets and install.... although the point made that your brake system is over a quarter century old is valid..however if brand new would still suck....start with calipers and work to master then booster..the secret to a succesful c5 upgrade is to remove the master and let out the little screw a few turns... the c5 caliper uses more fluid than c4s itle give the master piston a little help getting more fluid up front...pads are unfortunatly a personal thing try a few and see what u like..pm me for more help if u need it
pm me for more help if u need it
Team Owner
Joined: Mar 2001
Posts: 30,847
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
What class are you running in?
Any brake upgrade will bump your class.
I know people who have boiled their brake fluid with the early C4 brakes and an autocross
I have the later J55's, even they were cr@p until I switched from the stock pads.
I got Wilwoods for it now.
Any brake upgrade will bump your class.
I know people who have boiled their brake fluid with the early C4 brakes and an autocross
I have the later J55's, even they were cr@p until I switched from the stock pads.
I got Wilwoods for it now.
Intermediate
Joined: Jun 2011
Posts: 34
Likes: 0
please help............
my brakes sucks, sometimes it feels like there is no brakes at all. when i press on the brakes i hear some air sound. and the engine revs up a little. i checked for leakes no fluid leaks. plus the brake fluid is full. whats the problem...i know someone is going to suggest that there is a vacuum leak, so how do i check if its true and where can i find the hose and repair it. thank you.
my brakes sucks, sometimes it feels like there is no brakes at all. when i press on the brakes i hear some air sound. and the engine revs up a little. i checked for leakes no fluid leaks. plus the brake fluid is full. whats the problem...i know someone is going to suggest that there is a vacuum leak, so how do i check if its true and where can i find the hose and repair it. thank you.
Burning Brakes
Joined: Mar 2005
Posts: 800
Likes: 2
please help............
my brakes sucks, sometimes it feels like there is no brakes at all. when i press on the brakes i hear some air sound. and the engine revs up a little. i checked for leakes no fluid leaks. plus the brake fluid is full. whats the problem...i know someone is going to suggest that there is a vacuum leak, so how do i check if its true and where can i find the hose and repair it. thank you.
my brakes sucks, sometimes it feels like there is no brakes at all. when i press on the brakes i hear some air sound. and the engine revs up a little. i checked for leakes no fluid leaks. plus the brake fluid is full. whats the problem...i know someone is going to suggest that there is a vacuum leak, so how do i check if its true and where can i find the hose and repair it. thank you.
Intermediate
Joined: Jun 2011
Posts: 34
Likes: 0
Burning Brakes
Joined: Nov 2008
Posts: 995
Likes: 1
From: Naples Campania
Everyone hates their brakes. I'm saving my money to do a C5 kit.....as soon as I'm done buying all the other crap that I want :P
gerardvg made a good point above. If they do require a certain pad type, we might want to try it out.
jaa1992 also makes a good point. MAKE SURE YOU HAVE A HEALTHY SYSTEM BEFORE YOU START BUYING STUFF. Bent/ pinched hoses? How old is your fluid? S****y pads or discs? Maybe your brake booster is busted. That happens A LOT. If you are going to replace the brake booster, get the metal one.
Test, check, test, clean, test, replace, test then if you still aren't satisfied, buy the new stuff.
Le Mans Master
Joined: Mar 2001
Posts: 7,999
Likes: 14
From: Life is just one big track event. Everything before and after is prep and warm-up and cool-down laps
Cruise-In III Veteran
Cruise-In IV Veteran
St. Jude Donor '12
Yep, my J55's were marginal at the track until I replaced the booster, master, and all four calipers. Before I did that I was flushing the brake fluid after every event.
Now its a little bleed after an event to get the nasty overheated fluid out and full flush before the season and mid-year. I have enough points to stay in class and put a big brake kit on, just have no funds. I can tell you the bias spring, Carbotech XP12 and XP10 brake pads are fantastic after the warmup lap!
Now its a little bleed after an event to get the nasty overheated fluid out and full flush before the season and mid-year. I have enough points to stay in class and put a big brake kit on, just have no funds. I can tell you the bias spring, Carbotech XP12 and XP10 brake pads are fantastic after the warmup lap!
Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
I have an 85 which has the same brakes as the 84. They were really bad compared with what I am used to on my daily car.
Tried a lot of pads recommended from nice guys . Got better and better but far from good.
I was recommended new rotors and bought Powersplit and Hawk HPS pads. It became much better but still not as brakes on a sport car.
Changed the pads to Hawk HP plus and that was a quantum leap. Not only a good initial grip when cold but increasingly good when brakes became hot.
Now I am satisfied with brake performance, but the dusting is more than on stock ones and there is some squeel when braking in slow speed. This is not any problem for me as theperformance of the brakes is way over the stock.
With more friction the heat increases annd therefore I changed the brake fluid to Castrol SRF which has a very high temperature threshold.
Tried a lot of pads recommended from nice guys . Got better and better but far from good.
I was recommended new rotors and bought Powersplit and Hawk HPS pads. It became much better but still not as brakes on a sport car.
Changed the pads to Hawk HP plus and that was a quantum leap. Not only a good initial grip when cold but increasingly good when brakes became hot.
Now I am satisfied with brake performance, but the dusting is more than on stock ones and there is some squeel when braking in slow speed. This is not any problem for me as theperformance of the brakes is way over the stock.
With more friction the heat increases annd therefore I changed the brake fluid to Castrol SRF which has a very high temperature threshold.
