[BRAKES] Need help please :)
Thread Starter
Melting Slicks
Joined: Sep 2003
Posts: 3,474
Likes: 1
From: 1
[BRAKES] Need help please :)
I have a '93 LT1 & Brakes are weak. When braking hard the "SVC ABS", "SVC ASR", "BRAKES" lights all illuminate and stay on ("BRAKES" light goes out after a few sec and doesn't stay on). After turning the car off and then turning it back on, the lights go out.
I bought the service manuals at Carlisle and started reading through the brakes section. The manual says that those lights go on after the low fluid switch is tripped in the master cylinder. My fluid level isn't low though.
Is it possible that I have an air bubble inside one of the brake lines? I'm thinking that maybe the air bubble is being pushed into the master cylinder and causing the lights to go on, which would also be the reason for weak brakes.
On a side note- I have an LT4 Hotcam, but many people have said that it shouldn't effect the booster vacuum enough to cause horrible brakes.
Thanks in advance for any info. You guys are great
I bought the service manuals at Carlisle and started reading through the brakes section. The manual says that those lights go on after the low fluid switch is tripped in the master cylinder. My fluid level isn't low though.
Is it possible that I have an air bubble inside one of the brake lines? I'm thinking that maybe the air bubble is being pushed into the master cylinder and causing the lights to go on, which would also be the reason for weak brakes.
On a side note- I have an LT4 Hotcam, but many people have said that it shouldn't effect the booster vacuum enough to cause horrible brakes.
Thanks in advance for any info. You guys are great
Last edited by Darkgh0st; Aug 28, 2006 at 06:25 PM.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
describe weak brakes? soft pedal? hard pedal?
you can check the codes, too.
C4 Guru - Reading CCM Codes 1992/93
you can check the codes, too.
C4 Guru - Reading CCM Codes 1992/93
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I had my lights come on once and checked the fluid level and did not look low. I filled it more (had room) and it resolved the problem. Mine eventially set a code which I cleared thru the computer. The sensor just liked the fluid real full... at least on my car.
Off hand it sounds like 2 sepeate situations here. The weak brakes and the lights. If the adding fluid resoves the lights from coming on, then you can concecrtate on the weak brakes.
It sounds like you might have joined the rest of us with the C4 braking problems.
Off hand it sounds like 2 sepeate situations here. The weak brakes and the lights. If the adding fluid resoves the lights from coming on, then you can concecrtate on the weak brakes.
It sounds like you might have joined the rest of us with the C4 braking problems.
Last edited by pcolt94; Aug 30, 2006 at 11:13 AM.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Last time brake fluid was fully flushed? Last time brake pads changed?
Is your master cylinder working correctly? Brake booster ok?
Take a look at the above for starters and get back to us.
Is your master cylinder working correctly? Brake booster ok?
Take a look at the above for starters and get back to us.
Thread Starter
Melting Slicks
Joined: Sep 2003
Posts: 3,474
Likes: 1
From: 1
Last time brake fluid was fully flushed?
Never
Last time brake pads changed?
approx. 3 years
Is your master cylinder working correctly? Brake booster ok?
Both checked out by my mechanic and he said they are both good. The vacuum line to the booster was checked but not measured
Never
Last time brake pads changed?
approx. 3 years
Is your master cylinder working correctly? Brake booster ok?
Both checked out by my mechanic and he said they are both good. The vacuum line to the booster was checked but not measured
Thread Starter
Melting Slicks
Joined: Sep 2003
Posts: 3,474
Likes: 1
From: 1
Originally Posted by bogus
describe weak brakes? soft pedal? hard pedal?
you can check the codes, too.
C4 Guru - Reading CCM Codes 1992/93
you can check the codes, too.
C4 Guru - Reading CCM Codes 1992/93
Can't even come close to locking up the brakes or having ABS kick in. Also the lights I mentioned in the first post come on until the car is restarted.
Brakes are at their worst when the car is first started. Don't know if its because the pads are cold or because the vacuum pressure isnt there yet.
Last edited by Darkgh0st; Aug 29, 2006 at 10:10 AM.
Thread Starter
Melting Slicks
Joined: Sep 2003
Posts: 3,474
Likes: 1
From: 1
Originally Posted by pcolt94
I had my light come on once and checked the fluid level and did not look low. I filled it more (had room) and it resolved the problem. The sensor just liked the fluid real full... at least on my car.
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Pro
Joined: Apr 2000
Posts: 621
Likes: 1
From: Clarkston Mi
Based on the above discription of your panic test, I would like to also point at your booster.
When my booster went, the petal was very stiff, and didn't seem to stop the car very well. I never had a dummy light trip, though.
What sucks is that the 93 booster (and - I believe all standard C4s) is plastic. You get a crack, and it is done for. Ask around and see if you can get your hands on a ZR1 metal booster, with two blatters. You will have to do a little modification inside to make it work, though. I believe that the push rod is shorter.
When my booster went, the petal was very stiff, and didn't seem to stop the car very well. I never had a dummy light trip, though.
What sucks is that the 93 booster (and - I believe all standard C4s) is plastic. You get a crack, and it is done for. Ask around and see if you can get your hands on a ZR1 metal booster, with two blatters. You will have to do a little modification inside to make it work, though. I believe that the push rod is shorter.
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
2006 seems to be the year of the bad brakes. My problems are similar. I replaced the booster = no difference. Measured the vacuum going to the booster and it was only 12 psi (10 with the AC on). This is with a retarded Hotcam. I bought a vacuum canister from Summit = no difference. I'm going to pull the Autozone booster and see if I can get my money back and by a GM booster. My ABS/ASR are also squirlley, but that's a different problem. If worse comes to worse, I'll stick with manual brakes and hope that I don't have to make an emergency stop.
Thread Starter
Melting Slicks
Joined: Sep 2003
Posts: 3,474
Likes: 1
From: 1
Originally Posted by Lichen
2006 seems to be the year of the bad brakes. My problems are similar. I replaced the booster = no difference. Measured the vacuum going to the booster and it was only 12 psi (10 with the AC on). This is with a retarded Hotcam. I bought a vacuum canister from Summit = no difference. I'm going to pull the Autozone booster and see if I can get my money back and by a GM booster. My ABS/ASR are also squirlley, but that's a different problem. If worse comes to worse, I'll stick with manual brakes and hope that I don't have to make an emergency stop.
Did the canister improve your vacuum at all?
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Originally Posted by Darkgh0st
Last time brake fluid was fully flushed?
Never
Last time brake pads changed?
approx. 3 years
Is your master cylinder working correctly? Brake booster ok?
Both checked out by my mechanic and he said they are both good. The vacuum line to the booster was checked but not measured
Never
Last time brake pads changed?
approx. 3 years
Is your master cylinder working correctly? Brake booster ok?
Both checked out by my mechanic and he said they are both good. The vacuum line to the booster was checked but not measured
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Originally Posted by Lichen
2006 seems to be the year of the bad brakes. My problems are similar. I replaced the booster = no difference. Measured the vacuum going to the booster and it was only 12 psi (10 with the AC on). This is with a retarded Hotcam. I bought a vacuum canister from Summit = no difference. I'm going to pull the Autozone booster and see if I can get my money back and by a GM booster. My ABS/ASR are also squirlley, but that's a different problem. If worse comes to worse, I'll stick with manual brakes and hope that I don't have to make an emergency stop.
Melting Slicks
Joined: Nov 2002
Posts: 2,471
Likes: 2
From: 1993 Quasar Blue 'vert Scottsdale AZ
Originally Posted by edcmat-l1
Why would you retard the cam? Do you mean advanced? That did nothing but make the manifold vacuum worse. ADVANCE the cam and you'd get more vacuum AND more usable power, down low.