C4 Brakes
#1
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C4 Brakes
I HAVE A '94 AND JUST DID THE FRONT BRAKES( ROTOR AND PADS) CAUSE THEY WERE SHOT, GOT EM ALL DONE TESTED OUT AND WAS NOT TOO HAPPY, DO NOT STOP WELL AT ALL AND PEDAL IS LITTLE HARD, CHECKED FLUID AND REAR BRAKES ALL WAS FINE, I SAW SOME OTHER POST ON HERE AND SEEMS LIKE THIS IS JUST THE WAY THEY ARE FOR '94, AND ADVICE OR FIX FOR THE PROBLEM..THANKS GUYS
#2
Safety Car
Not sure if this really applies here or not, but I have heard stories that clearing the stored codes in the ABS ECM module can help with braking performance. You can do it with the paperclip method, or using an OBDI scanner.
#7
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A hard brake pedal is a symptom of a worn brake booster.
Have a Qualified brake shop check the ABS system as well. Your brakes should work and feel like any other vehicle when working properly.
Have a Qualified brake shop check the ABS system as well. Your brakes should work and feel like any other vehicle when working properly.
#8
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sorry guys i meant the pedal has to be pressed hard, pedal is soft when pressed in....any other ideas or suggestions, gonna start with reset of abs
#9
Burning Brakes
What kind of pads and how did you break them in?
If they were brought up to temp. too quickly the pads can "glaze" and they will feel like wood. No friction and you have to press the peddle hard to get them to work.
If they were broken in properly and you still don't like the feel then try taking them back.
If they were brought up to temp. too quickly the pads can "glaze" and they will feel like wood. No friction and you have to press the peddle hard to get them to work.
If they were broken in properly and you still don't like the feel then try taking them back.
#10
Le Mans Master
I have heard clearing the codes will affect brake performance. Personally I don’t believe it and have never heard a technical reason yet why it will affect it. If the ABS was disabled by the codes, then you would have no anti-skid and max braking. If ABS kicks in, it then RELEASES pressure to the wheel cylinders and braking power. However if you want to try it, here is some info.
You can clear the brake codes in module 9.0. First you have to find out if you have any codes in the first place. Disconnecting the battery will not clear codes for the (EBTCM module) brakes in module 9, it has to be done by using the on board diagnostic system (or a Tech 1, etc) using segment 9.7 to reset and clear any codes.
As in regard to your hard pedal issue. Just make sure you check out the brake booster to make sure its OK. No engine running, pedal should be very firm at the top. With engine running, pedal should drop about 2 inches as foot pressure is increased.
As so many others with the C4 braking as an issue, as miles of posts and facts and opinions have been written. I did much work on mine replacing everything and having no real gain as I desired. Many have gone further then me measuring hydraulic pressures and such. I ended up upgrading to the J55, 13 inch system to get any real performance gain that I was looking for. I just don’t think there is enough friction in the front brakes to stop the car safely, and much more can be said on this to.
Seems like different quality front pads do make a difference as some have documented. I am still using the pads that came with my J55 setup, so why change when things are good.
Many have posed that braking performance is good using the Hawk HPS & HP plus. Probably when I need pads I will try the Hawks also.
Best of luck finding a combination that will work for you.
You can clear the brake codes in module 9.0. First you have to find out if you have any codes in the first place. Disconnecting the battery will not clear codes for the (EBTCM module) brakes in module 9, it has to be done by using the on board diagnostic system (or a Tech 1, etc) using segment 9.7 to reset and clear any codes.
As in regard to your hard pedal issue. Just make sure you check out the brake booster to make sure its OK. No engine running, pedal should be very firm at the top. With engine running, pedal should drop about 2 inches as foot pressure is increased.
As so many others with the C4 braking as an issue, as miles of posts and facts and opinions have been written. I did much work on mine replacing everything and having no real gain as I desired. Many have gone further then me measuring hydraulic pressures and such. I ended up upgrading to the J55, 13 inch system to get any real performance gain that I was looking for. I just don’t think there is enough friction in the front brakes to stop the car safely, and much more can be said on this to.
Seems like different quality front pads do make a difference as some have documented. I am still using the pads that came with my J55 setup, so why change when things are good.
Many have posed that braking performance is good using the Hawk HPS & HP plus. Probably when I need pads I will try the Hawks also.
Best of luck finding a combination that will work for you.
#11
Safety Car
You may need to bleed the whole system if you have a soft pedal, but also check the booster as stated above. Hawk HPS pads are what I used, and the difference was amazing.
Good luck.
Good luck.
Last edited by RandyJ75; 03-17-2008 at 09:28 PM.
#12
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CI 1-2-3-4-5-6-7-8 Veteran
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It sounds as if your pads were not properly seated/bedded. I would R/R the pads and rough the surface of them up a bit with some sandpaper. You dont need to do much, just scuff them a bit and try to bed them in properly. You could try getting the brakes up to temp then finding an open area or large parking lot. Then get the car up to some speed in REVERSE and making several panic stops in REVERSE. This will help to 'cut' the new pads in a different direction and fills the backside of the small voids/imperfections on new rotors. I've done it many times when I worked at the dealership and in many cases it had dramatic (positive) results.
Note: when I had the most success with this method it was usually due to someone else at the dealership having done the brakes earlier and I got stuck with the rework/return. It allmost allways was the result of someone not knowing how to properly resurface rotors and then not bedding them in correctly. That ringing noise you often hear like someone running their finger around the top of a crystal glass....thats called chattering wile the rotor is being turned. It should not make that noise. Just FYI.
Note: when I had the most success with this method it was usually due to someone else at the dealership having done the brakes earlier and I got stuck with the rework/return. It allmost allways was the result of someone not knowing how to properly resurface rotors and then not bedding them in correctly. That ringing noise you often hear like someone running their finger around the top of a crystal glass....thats called chattering wile the rotor is being turned. It should not make that noise. Just FYI.
#13
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dr evil, i actually have that noise coming from the back right one, i thought it was a lose wheel, i tightened up but that wasnt the case, the pads are ok in rear but rotors have some wear and groves in them...the noise is very similar to what you described..only does it when you start out in reverse and forward..any advise or fix to this..thanks
#15
Is the pedal spongy? or is the pedal firm, and you must apply a alot of pressure to get a good bite?
Pads have different coefficient's of friction. What brand and model pad did you use?
I've seen huge changes in pedal feel from pad changes. (not in a vette but many other cars)
Pads have different coefficient's of friction. What brand and model pad did you use?
I've seen huge changes in pedal feel from pad changes. (not in a vette but many other cars)
#16
Pro
ABS self test
As far as I know this applies to ALL C4s. The ABS will test itself upon start up of the vehicle. The driver gets physical feed back of this test as soon as you start to drive. Just rest your foot on the brake pedal very lightly and you will feel a light kick back in the pedal before you reach 5mph.
If you don't get that kick back it is time to check the ABS codes. It's all spelled out in the shop book.
If you don't get that kick back it is time to check the ABS codes. It's all spelled out in the shop book.
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#18
Le Mans Master
I HAVE A '94 AND JUST DID THE FRONT BRAKES( ROTOR AND PADS) CAUSE THEY WERE SHOT, GOT EM ALL DONE TESTED OUT AND WAS NOT TOO HAPPY, DO NOT STOP WELL AT ALL AND PEDAL IS LITTLE HARD, CHECKED FLUID AND REAR BRAKES ALL WAS FINE, I SAW SOME OTHER POST ON HERE AND SEEMS LIKE THIS IS JUST THE WAY THEY ARE FOR '94, AND ADVICE OR FIX FOR THE PROBLEM..THANKS GUYS
Last edited by runner140*; 03-19-2008 at 08:29 AM.