Hard brake pedal solution, finally!!
#1
Burning Brakes
Thread Starter
Hard brake pedal solution, finally!!
I know I am not the only guy that has complained of a hard brake pedal on a late model C4. My 94 brakes have always been terrible, In spite of upgrades over time of new rotors, quality pads, stainless lines, J55 upgrade, and a new M cylinder. The brakes still sucked. They always felt like they had no boost even though the unit checked out and worked normally. I finally broke down and decided to let someone else work on my car (I hate doing that you know) by taking it to Corvette Masters in Orlando.
With the ability to read the ABS unit it turned out that there were 3 codes stored in my computer. Even though the light came on when you started the car, the ABS went through the self check and then the light went off, ( in other words it acted as it should) the 3 codes that were in it were somehow preventing my brakes from working normally. They cleared the codes, went through the diagnostics on the unit to insure it was OK, and voila! I have brakes now.
I know I have seen lots of guys complain about this, and I would have never suspected the solution could have been so simple. So if your brake pedal requires way too much effort to stop the car and there seems to be no reasonable solution to it, I would strongly reccomend you have someone look into the ABS units subconscious mind and perform the necessary brain surgery.
Thank you Corvette Masters!
Roy
With the ability to read the ABS unit it turned out that there were 3 codes stored in my computer. Even though the light came on when you started the car, the ABS went through the self check and then the light went off, ( in other words it acted as it should) the 3 codes that were in it were somehow preventing my brakes from working normally. They cleared the codes, went through the diagnostics on the unit to insure it was OK, and voila! I have brakes now.
I know I have seen lots of guys complain about this, and I would have never suspected the solution could have been so simple. So if your brake pedal requires way too much effort to stop the car and there seems to be no reasonable solution to it, I would strongly reccomend you have someone look into the ABS units subconscious mind and perform the necessary brain surgery.
Thank you Corvette Masters!
Roy
#2
Burning Brakes
I've had a similar problem with my 92. I changed out the lines to Stainless and it's still hard. I was getting ready to take a look at the booster and maybe replace it but now I'm going to have to check the system for codes.
Thanks for the post.
Thanks for the post.
#4
....interesting..i have an 88 and have been chasing crappy "fred flintstone" brakes for 2 years after multiple bleedings, flushings, m/c change-out, s/s flex lines, new pads, new rotors, and new ck valve, where the booster cks good and holds vacuum..........is there wa way to "clear" the codes on the 88 if it so applies?....
Last edited by Da Mail Man; 07-27-2007 at 09:46 PM. Reason: spelling
#5
Team Owner
Member Since: May 2002
Location: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
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You may be on to something big here. Some members say it's fine, others say theirs are unbelievably bad.
Another guy with bad brakes pulled the fuse on his ABS and said it felt like a whole new car.
Pulling the fuse could be a quick check to see if it is the ABS, before going in for a scan.
Another guy with bad brakes pulled the fuse on his ABS and said it felt like a whole new car.
Pulling the fuse could be a quick check to see if it is the ABS, before going in for a scan.
#9
Burning Brakes
Thread Starter
As best as I can read my copy the codes stored were:
C0063 Valve relay circuit malfunction
C0065 Adjuster circuit assembly malfunction
c0023? Low brake fluid.
Roy
#10
Burning Brakes
Thread Starter
#12
Le Mans Master
brakes
86E, new master, new front calipers, new booster, new front pads.
the brakes were always a sore spot with me, and I gradually figured that the booster was under engineered for the car.
I was planning on maybe stepping up to a dual piston caliper.
Now, I may play with the electronics a little to see if it's something else.
Come to think of it, my rear pads seem to last forever.
Maybe the ABS has sufficiently shut off the fluid to the rears, and that's why it is hard to stop, and the pads last a long time.
Sigh.......another area that The General kept a secret that I have to unlock.........
the brakes were always a sore spot with me, and I gradually figured that the booster was under engineered for the car.
I was planning on maybe stepping up to a dual piston caliper.
Now, I may play with the electronics a little to see if it's something else.
Come to think of it, my rear pads seem to last forever.
Maybe the ABS has sufficiently shut off the fluid to the rears, and that's why it is hard to stop, and the pads last a long time.
Sigh.......another area that The General kept a secret that I have to unlock.........
#13
Le Mans Master
I believe this information is good for 92-94, possibly 95, and not sure about 96 since it is OBDII.
I’m not arguing with success, but a code is an indication of a fault or problem. The code can always be cleared but if the problem is not fixed, the code will be reset. The code is used to lead you to a problem area so the trouble can be repaired. So I don’t understand how clearing a code can make a brake system or for that mater, anything work better as if it was repaired.
I would need a real good technical explanation, that would be believable to me. Like the valves in the pump were restricting fluid flow with out the pump running. Pulling the fuse or power to it should disable any solenoid action in the ABS pump.
I happen to know the guys at Corvette Masters and they are a knowledgeable group also that helped me out once and have spoke with on several occasions. They use a tech 2 which they probably used to clear the codes.
I sure would like to hear the rest of the story if there is one.
#14
Team Owner
Member Since: May 2002
Location: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Posts: 24,337
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86E, new master, new front calipers, new booster, new front pads.
the brakes were always a sore spot with me, and I gradually figured that the booster was under engineered for the car.
I was planning on maybe stepping up to a dual piston caliper.
Now, I may play with the electronics a little to see if it's something else.
Come to think of it, my rear pads seem to last forever.
Maybe the ABS has sufficiently shut off the fluid to the rears, and that's why it is hard to stop, and the pads last a long time.
Sigh.......another area that The General kept a secret that I have to unlock.........
the brakes were always a sore spot with me, and I gradually figured that the booster was under engineered for the car.
I was planning on maybe stepping up to a dual piston caliper.
Now, I may play with the electronics a little to see if it's something else.
Come to think of it, my rear pads seem to last forever.
Maybe the ABS has sufficiently shut off the fluid to the rears, and that's why it is hard to stop, and the pads last a long time.
Sigh.......another area that The General kept a secret that I have to unlock.........
#17
Burning Brakes
Thread Starter
No.
I’m not arguing with success, but a code is an indication of a fault or problem. The code can always be cleared but if the problem is not fixed, the code will be reset. The code is used to lead you to a problem area so the trouble can be repaired. So I don’t understand how clearing a code can make a brake system or for that mater, anything work better as if it was repaired.
I would need a real good technical explanation, that would be believable to me. Like the valves in the pump were restricting fluid flow with out the pump running. Pulling the fuse or power to it should disable any solenoid action in the ABS pump.
I’m not arguing with success, but a code is an indication of a fault or problem. The code can always be cleared but if the problem is not fixed, the code will be reset. The code is used to lead you to a problem area so the trouble can be repaired. So I don’t understand how clearing a code can make a brake system or for that mater, anything work better as if it was repaired.
I would need a real good technical explanation, that would be believable to me. Like the valves in the pump were restricting fluid flow with out the pump running. Pulling the fuse or power to it should disable any solenoid action in the ABS pump.
I am not sure he had a technical explanation for it, I think if he did he would have given it to me. It was simply the last possible place to look for a problem given everything else I had done to the car.
I assume something was simply stuck the wrong direction inside of that thing. But you know what happens when you assume things.....
Roy
#18
Burning Brakes
Although I don't understand how clearing the codes without addressing the underlying problems would correct any "Hard Brake" symptoms, if it works; GREAT!
It isn't necessary to use a Tech-1 scanner to clear the codes on OBD-I cars. They can be cleared by using a U shaped piece of wire (paper clip) inserted into the "A" and "H" pins of the ALDL socket.
1. Turn the ignition "Off"
2. Ground pin "H" to pin "A"
3. Turn the ignition "ON"
4. Wait for the code to begin flashing.
5. Unground pin "H" from pin "A" for at least one second, then reground it. This must be done three (3) times within ten (10) seconds
6. Wait at least 15 seconds before turning the ignition "OFF". The verify that Code 12 is the only code being flashed. If not, the codes haven't been properly cleared and you must repeat the procedure.
The computer will also clear a code if it doesn't reappear after 100 engine on/off cycles.
It isn't necessary to use a Tech-1 scanner to clear the codes on OBD-I cars. They can be cleared by using a U shaped piece of wire (paper clip) inserted into the "A" and "H" pins of the ALDL socket.
1. Turn the ignition "Off"
2. Ground pin "H" to pin "A"
3. Turn the ignition "ON"
4. Wait for the code to begin flashing.
5. Unground pin "H" from pin "A" for at least one second, then reground it. This must be done three (3) times within ten (10) seconds
6. Wait at least 15 seconds before turning the ignition "OFF". The verify that Code 12 is the only code being flashed. If not, the codes haven't been properly cleared and you must repeat the procedure.
The computer will also clear a code if it doesn't reappear after 100 engine on/off cycles.
#19
Le Mans Master
I am familiar with the limp home mode for the engine, but not for the brake system. If I should come across it reading the bible (FSM), I will sure tell all.
I have a vested interest in strange brake problems, for I fought one myself on my C4. It was just poor braking, replaced it all except the brake computer and booster which performed fine. Installed the J55 system and finally got good brakes but wish I could have made the original system work normal and safe. So I’m always interested in any new information that might shed light on the illusive brake problems of the early 90 C4s with ABS.
FASTMAX - Thanks for the reply and best of luck on your good brakes.