I am concerned with my brakes on my 1990, especiall after testing the speedo system on this car and having the front on ramps and spinning the rear tires. I basically couldn't stop the rear tires with the brakes at all. I also got a serv. abs warning on the DIC.

My brake pedal always seemed to go excessively far down. I have driven a car with abs before and it did nothing like what this brake pedal did. The master cylinder is completely full, I see no leaks anywhere, vacumn is hooked up.

I am not sure if this car has base brakes or the larger brakes. I know it's a FE1 so I doubt it has large brake, which I also don't see the need for anyways.

Are brake issues like this common with these cars and if not where is a good place to start fixing this problem or should I leave it to a dealership since the abs seems to be involved with this issue.

 

Brakes have been a problem on the C4 and have been a big topic of conversation. Not many posts recently but a few years back a lot. Try searching using different key words.

I hate to say it s common but my 94 does the same with the rears off the ground and engine running in gear. It is tough to stop the rears. What ever the engineering reasons and there might be several, the rears are seemingly under-braked.

The front brakes are no great bargain either as to why so many things have been tried to improve the C4 braking. When the J55 13” brakes came out they were an improvement in stopping performance. Then DRM motor sports came out with a change in the master proportional valve spring which balanced out the brake system so it would not be over braked in the front so much. My brakes were down right lousy, I replaced everything with no real improvement until it changed over the J55 system.

You might have got an ABS warning light because the difference in speed between the front and rear wheels. Obviously the fronts are not turning and the brake computer compares wheel speeds from each wheel pickup sensor.

There is many options and parts for the front brakes to try. Pads, rotors etc different calipers. But there is almost nothing or real value for the rears other than trying pads and new rotors. You might consider steel braded flex lines.

 

I've a 90 with the J56's and they were alright from the factory, JMHO. As the car was getting on in yrs I decided to start renewing things. This is what I did and I got some very nice results.

Rear caliper kits to rebuild the rears.
New M/C plus a DRM Bias spring.
Front caliper kits to do front calipers.
Set of speed bleeders.
stayed with stock type pads. Not GM, but Performance Friction.
S/S lines from Earls @ summitt, only because the lines were original.
Rotors were not out, so I had a just a finish cut put to them.

The results were a nice improvement, next I went to DRM and bought their GS calipers with s/s pistons and got a set of new rotors. I was going to get Power slot rotors from Wagoner, but then I saw a clearance sale on some stuff rotors on line, drilled & slotted. I figured they would be nice bling to go with the powder coated DRM calipers.

The final result was a really noticable improvement. I was very pleased. I suspect that just slotted rotors would have given the same results. It's just that the ones I bought were killer price.

Look on the under side of the console lid and you will find all the RPO codes, if you see J56 then you have a great starting point. If you don't have J56, then I would look into doing the C5 front caliper & rotor conversion. That will wake up the std brake package if that is what you have. I can PM you a coupla of links for places to get the C5 conversion package.

I should mention that I tried first flushing the fluid as I'm the second owner on my car. The fluid was 15 yrs old. I had it done with a Tech1A & a pressure bleeder and there was still old fluid trapped in the calipers when I took them down!

I hope that this stuff gives you something to use as a starting point. Good luck!


Tom

 

I'm thinking you got the ABS warning maybe because the front tires were on the ramps and not rotating while the rears were.

Maybe, the pedal going down too far is the master cylinder getting old and tired. If it were my car I'd change the master cylinder, flush the system and put new fliud in.

 

my brakes are garbage and the problem is obvious... why would the brake pads for a CORVETTE be small enough to fit in the palm of my hand? Needs bigger calipers/pads. Yes I know the J55's are not quiet this small but go to the parts store and look at one for an early vette.

 

Nobody is going to argue with you as you point is well taken.

The J55s use the same pad as the original 12” system. The pad doesn’t even cover the entire surface of the 13” rotor.

Why they did not put a high performance brake system on a high performance car beats me.

 

Have you tried bleeding the brakes? A spongy feeling pedal could just be air in the lines, or a new master cylinder like someone mentioned. When you hit the brakes, release the pedal then quickly press it again. If it gets any stiffer its air, if not its probably the master cylinder.

 

One other thing I forgot to mention about my brakes. When I was doing the head gaskets somehow I destroyed a sensor on the master cylinder. this sensor has two wires going to it I believe.

I'm not sure a brake upgrade would suit the purpose I have for this car and thats just a everyday driver. Maybe when I do decide to race it against my best friend on a track then I will. But for now my main thing for the car is just daily going to work car, hauling my son to school etc.

I also not sure how long this car has been sitting but if it's registration stickers are true, then the car hasn't been driven in well over 2 years. So I don't know if the calipers could be sticking or what.

 

At the time they were high performance brakes, we going back a few years remember.

Best thing I've done to my J55's is the pads.

 

Well, I ran the vette again for about a 1/2 hour. However this time I did not spin the tires. I Tried the brakes in gear and they hold the car fine, I also pumped the brake pedal many times and never got the abs service light on the DIC .... So what the one guy said about the rears spinning and the fronts stopped is what caused the abs service light.

with the front tires stopped and the rear tires spinning could the abs be why the rear brakes wouldn't work as well? I basically did this to see if the speedometer worked on the car so ran the rear tires up to about 25mph. One weird thing that happened though was the speedo didnt start working till it seemed like the car shifted into 2nd gear.

I'm going to replace the soft lines with steel braided ones for sure. Maybe that will get rid of the spongy pedal feeling. My brake pedal however does not go to the floor, the brake fluid seems pretty clean in the resovoir but w3ill have it all changed.

so do you think I have sticking rear calipers/abs issues .... or what happened normal