1988 Vette hard brake line size to ABS
07-20-2018, 01:25 PM
#21
Safety Car
That looks like it was a REAL "P.I.A." to do. I too have a 1988 C4 coupe that had rust on all the lines as they went into the ABS unit. When I was getting the car ready to drive one day I stepped hard on the brakes and the pedal went to the floor. The line furthest to the center of the car on the ABS unit was the culprit. After doing an inspection of my other lines I contacted Classic Tube and ordered a standard steel set of the entire brake line kit. It cost me way less than Corvette Central to buy them direct from the manufacturer.
Just so you know, Classic Tube also offers a set of brake lines so you can eliminate the ABS unit if you so desire. I was surprised when working on my car that one of the brake lines coming out of the ABS unit looked like i had eaten a small olive. That was more evidence of water in the system. I flushed out my ABS unit and sealed it up until I can finish it. Having five crushed discs in my back might force me to take the car to my favorite mechanic and let them seal my brake system back up for me.
In your pictures the lines on your car look way, way better than the ones I have. Are you using the Steel hardware for splicing your lines? They sell brass brake parts at the local Advanced Auto, I went to NAPA and got the correct Steel ones that are designed for this application. The steel ones come with a steel olive or whatever they call that little sleeve that digs into the brake line to seal it. The brass ones are softer than the steel and don't seal well enough from what I read. My mechanic said that they will not pass the car for safety inspection in Virginia if they find the brass fittings on the brake system
The 1988 C4 brake system is most interesting and our master cylinder is a unique to 1988 part. I was shocked when I found that the two lines from the master cylinder were "supply" and "return". On the 1988 the four corners are actually three, "front right", "front left" and "Rear". What I found most disturbing was the minute I had a leak in the brake lines that the pedal went to the floor and would not pump up or anything. I thought cars after 1964 were supposed to have two reservoirs to allow either the front or rear brakes to leak or fail without loosing your brake pedal completely. Not so on my car, one little leak and bang the whole system goes away. For this reason alone I will always have a very functional e-brake, this is one place where it is good to have the 1988 over the 1987 and earlier models. We have a modern emergency brake that works great, no more little stainless brake shoes for the e-brake. I oil the cables every year and oil the mechanism and the E-brake works great. I was dissapointed to find that my daughters 2011 Camaro has the little brake shoes type E-brake. They do not hold as well in my opinion, I have that system on my 1968 C3 but made it work as best I could, It holds the car.
While working on my car I found the lateral acceleration sensor had broken loose at some point. I re-secured it in the original position and now I am anxious to see if there is any difference.
I use a Phoenix Systems "reverse brake bleeder" and that puppy really helps with the ABS unit getting bled properly and thoroughly. A very useful tool, it makes bleeding brakes a cinch, it also is a life saver trying to bleed a GM hydraulic clutch master cylinder. It is so simple now that I bleed the brakes every five years (at least) on every car and motorcycle that I own. This is one of the few tools that has made Corvette ownership easier if you do your own work.
Good luck with getting your car back on the road with the stopping power Corvettes are known for!
Just so you know, Classic Tube also offers a set of brake lines so you can eliminate the ABS unit if you so desire. I was surprised when working on my car that one of the brake lines coming out of the ABS unit looked like i had eaten a small olive. That was more evidence of water in the system. I flushed out my ABS unit and sealed it up until I can finish it. Having five crushed discs in my back might force me to take the car to my favorite mechanic and let them seal my brake system back up for me.
In your pictures the lines on your car look way, way better than the ones I have. Are you using the Steel hardware for splicing your lines? They sell brass brake parts at the local Advanced Auto, I went to NAPA and got the correct Steel ones that are designed for this application. The steel ones come with a steel olive or whatever they call that little sleeve that digs into the brake line to seal it. The brass ones are softer than the steel and don't seal well enough from what I read. My mechanic said that they will not pass the car for safety inspection in Virginia if they find the brass fittings on the brake system
The 1988 C4 brake system is most interesting and our master cylinder is a unique to 1988 part. I was shocked when I found that the two lines from the master cylinder were "supply" and "return". On the 1988 the four corners are actually three, "front right", "front left" and "Rear". What I found most disturbing was the minute I had a leak in the brake lines that the pedal went to the floor and would not pump up or anything. I thought cars after 1964 were supposed to have two reservoirs to allow either the front or rear brakes to leak or fail without loosing your brake pedal completely. Not so on my car, one little leak and bang the whole system goes away. For this reason alone I will always have a very functional e-brake, this is one place where it is good to have the 1988 over the 1987 and earlier models. We have a modern emergency brake that works great, no more little stainless brake shoes for the e-brake. I oil the cables every year and oil the mechanism and the E-brake works great. I was dissapointed to find that my daughters 2011 Camaro has the little brake shoes type E-brake. They do not hold as well in my opinion, I have that system on my 1968 C3 but made it work as best I could, It holds the car.
While working on my car I found the lateral acceleration sensor had broken loose at some point. I re-secured it in the original position and now I am anxious to see if there is any difference.
I use a Phoenix Systems "reverse brake bleeder" and that puppy really helps with the ABS unit getting bled properly and thoroughly. A very useful tool, it makes bleeding brakes a cinch, it also is a life saver trying to bleed a GM hydraulic clutch master cylinder. It is so simple now that I bleed the brakes every five years (at least) on every car and motorcycle that I own. This is one of the few tools that has made Corvette ownership easier if you do your own work.
Good luck with getting your car back on the road with the stopping power Corvettes are known for!
07-20-2018, 02:35 PM
#22
Safety Car
Thread Starter
That looks like it was a REAL "P.I.A." to do.
Yes it was! It was hovering around 95* and leaning into the car and into the cargo section to get to the ABS was difficult.
I too have a 1988 C4 coupe that had rust on all the lines as they went into the ABS unit. When I was getting the car ready to drive one day I stepped hard on the brakes and the pedal went to the floor.
Pretty much, that is what happened to me. I saw brake fluid on the ground that was leaking from the rear seal of the master cylinder. I wound up spending $100 for a lifetime guarantee unit that I installed the day after I bought it. While bleeding the master cylinder, I reconnected the lines, started pumping the brakes, and found they were going to the floor. I looked under the car and found brake fluid behind the driver's rear wheel.
The line furthest to the center of the car on the ABS unit was the culprit.
Mine was the second line in from the center of the car.
After doing an inspection of my other lines I contacted Classic Tube and ordered a standard steel set of the entire brake line kit. It cost me way less than Corvette Central to buy them direct from the manufacturer.
I looked around to a few places and found I can get an entire full steel set for between $200 and $250.
Just so you know, Classic Tube also offers a set of brake lines so you can eliminate the ABS unit if you so desire.
Nope, I do not wish to eliminate the ABS unit but, there is a post somewhere that lists the parts to combine the lines to eliminate the unit.
I was surprised when working on my car that one of the brake lines coming out of the ABS unit looked like i had eaten a small olive. That was more evidence of water in the system. I flushed out my ABS unit and sealed it up until I can finish it. Having five crushed discs in my back might force me to take the car to my favorite mechanic and let them seal my brake system back up for me.
All my lines seem to have a lot of surface rust on them from my first visual inspection. After I got underneath the car and took a good look, I found a lot of surface rust but, the lines generally looked in pretty good shape. After replacing the line, I "sleeved" them with vac tubing.
In your pictures the lines on your car look way, way better than the ones I have. Are you using the Steel hardware for splicing your lines?
I believe I am. Yes, but, the hard lines are not.
They sell brass brake parts at the local Advanced Auto, I went to NAPA and got the correct Steel ones that are designed for this application. The steel ones come with a steel olive or whatever they call that little sleeve that digs into the brake line to seal it.
I did some research and what I can determine was that a compression fitting or a compression "fix" was not recommended for doing brake lines due to the high pressure. It would be okay for low pressure lines such as, but not limited to, fuel lines and transmission lines.
The brass ones are softer than the steel and don't seal well enough from what I read. My mechanic said that they will not pass the car for safety inspection in Virginia if they find the brass fittings on the brake system.
I looked at getting steel lines but, opted for the type of line listed in my thread. It is DOT approved and is infinitely easier to bend and shape than the steel lines. I had to buy a different flaring tool since the one I had would only do your "typical" standard flare. Someone posted a picture of a bubble flare and a double flare (I think) as a comparison between the two and I matched up the type of flare used on my '88. I practiced four or five times on a piece of quarter inch copper line that I had laying around so that I could make and use the proper technique in making the flare required. I snapped a couple of insignificant bolts off for a plastic cover where the ABS brake lines enter/exit the ABS compartment. As it stands right now, I have crappy brakes but, I seemingly always had crappy brakes compared to my 1981. Could be because I have quite a bit of rust on the rotors but, I doubt it. The pedal is significantly firmer whether the car is running or not. The vacuum booster appears to work without any leaks or issues based on the tests I performed.
The 1988 C4 brake system is most interesting and our master cylinder is a unique to 1988 part. I was shocked when I found that the two lines from the master cylinder were "supply" and "return". On the 1988 the four corners are actually three, "front right", "front left" and "Rear". What I found most disturbing was the minute I had a leak in the brake lines that the pedal went to the floor and would not pump up or anything. I thought cars after 1964 were supposed to have two reservoirs to allow either the front or rear brakes to leak or fail without loosing your brake pedal completely. Not so on my car, one little leak and bang the whole system goes away. For this reason alone I will always have a very functional e-brake, this is one place where it is good to have the 1988 over the 1987 and earlier models.
Agreed. A relative has an 86 Vette and if I remember correctly, that only had one break reservoir.
We have a modern emergency brake that works great, no more little stainless brake shoes for the e-brake.
In my 74 Corvette, that was a major pain in the a$$ to access and change out the parking brakes! In that car, I put in all new bushings on the rear end, bearings, seals, and u-joints on the half shafts. A very crappy design to say the least! I got rained out today so, I have not had an opportunity to screw around and determine why the center dash display is lit up "BRAKES". It wasn't lit up when I took the car around the block. I possibly, have to take it out on the highway with little traffic present and get the rust off the rotors although, I would think that the rust would provide more friction. In the past few months, I have removed all the window tint on the vehicle including the back glass which was a major bitch, replaced an inner door window regulator, outer window weather strips on the doors, front hood lift pistons, back glass lift pistons, weather stripping around the front windshield, and all weather stripping for the one piece removable top. I am losing interest in this car very quickly!
I oil the cables every year and oil the mechanism and the E-brake works great. I was dissapointed to find that my daughters 2011 Camaro has the little brake shoes type E-brake. They do not hold as well in my opinion, I have that system on my 1968 C3 but made it work as best I could, It holds the car.
I tested mine out the other day when I encountered the brake light being lit on my dash and it appears to hold very well. Now I've got to figure out why that damn light is on and I don't think it is a sticking parking brake switch.
While working on my car I found the lateral acceleration sensor had broken loose at some point. I re-secured it in the original position and now I am anxious to see if there is any difference.
I use a Phoenix Systems "reverse brake bleeder" and that puppy really helps with the ABS unit getting bled properly and thoroughly. A very useful tool, it makes bleeding brakes a cinch, it also is a life saver trying to bleed a GM hydraulic clutch master cylinder. It is so simple now that I bleed the brakes every five years (at least) on every car and motorcycle that I own. This is one of the few tools that has made Corvette ownership easier if you do your own work.
I used to use a Mighty-Vac to bleed my brakes until I switched over to speed-bleeders. I was very skeptical about those since I can't see the fluid going into a clear mason jar to determine when the bubbles have ceased and the air is out of the lines. They seem to work well and the whole system bled out very well.
Good luck with getting your car back on the road with the stopping power Corvettes are known for!
If I can get my brakes back to what my 1981 had, I would be happy.
Yes it was! It was hovering around 95* and leaning into the car and into the cargo section to get to the ABS was difficult.
I too have a 1988 C4 coupe that had rust on all the lines as they went into the ABS unit. When I was getting the car ready to drive one day I stepped hard on the brakes and the pedal went to the floor.
Pretty much, that is what happened to me. I saw brake fluid on the ground that was leaking from the rear seal of the master cylinder. I wound up spending $100 for a lifetime guarantee unit that I installed the day after I bought it. While bleeding the master cylinder, I reconnected the lines, started pumping the brakes, and found they were going to the floor. I looked under the car and found brake fluid behind the driver's rear wheel.
The line furthest to the center of the car on the ABS unit was the culprit.
Mine was the second line in from the center of the car.
After doing an inspection of my other lines I contacted Classic Tube and ordered a standard steel set of the entire brake line kit. It cost me way less than Corvette Central to buy them direct from the manufacturer.
I looked around to a few places and found I can get an entire full steel set for between $200 and $250.
Just so you know, Classic Tube also offers a set of brake lines so you can eliminate the ABS unit if you so desire.
Nope, I do not wish to eliminate the ABS unit but, there is a post somewhere that lists the parts to combine the lines to eliminate the unit.
I was surprised when working on my car that one of the brake lines coming out of the ABS unit looked like i had eaten a small olive. That was more evidence of water in the system. I flushed out my ABS unit and sealed it up until I can finish it. Having five crushed discs in my back might force me to take the car to my favorite mechanic and let them seal my brake system back up for me.
All my lines seem to have a lot of surface rust on them from my first visual inspection. After I got underneath the car and took a good look, I found a lot of surface rust but, the lines generally looked in pretty good shape. After replacing the line, I "sleeved" them with vac tubing.
In your pictures the lines on your car look way, way better than the ones I have. Are you using the Steel hardware for splicing your lines?
I believe I am. Yes, but, the hard lines are not.
They sell brass brake parts at the local Advanced Auto, I went to NAPA and got the correct Steel ones that are designed for this application. The steel ones come with a steel olive or whatever they call that little sleeve that digs into the brake line to seal it.
I did some research and what I can determine was that a compression fitting or a compression "fix" was not recommended for doing brake lines due to the high pressure. It would be okay for low pressure lines such as, but not limited to, fuel lines and transmission lines.
The brass ones are softer than the steel and don't seal well enough from what I read. My mechanic said that they will not pass the car for safety inspection in Virginia if they find the brass fittings on the brake system.
I looked at getting steel lines but, opted for the type of line listed in my thread. It is DOT approved and is infinitely easier to bend and shape than the steel lines. I had to buy a different flaring tool since the one I had would only do your "typical" standard flare. Someone posted a picture of a bubble flare and a double flare (I think) as a comparison between the two and I matched up the type of flare used on my '88. I practiced four or five times on a piece of quarter inch copper line that I had laying around so that I could make and use the proper technique in making the flare required. I snapped a couple of insignificant bolts off for a plastic cover where the ABS brake lines enter/exit the ABS compartment. As it stands right now, I have crappy brakes but, I seemingly always had crappy brakes compared to my 1981. Could be because I have quite a bit of rust on the rotors but, I doubt it. The pedal is significantly firmer whether the car is running or not. The vacuum booster appears to work without any leaks or issues based on the tests I performed.
The 1988 C4 brake system is most interesting and our master cylinder is a unique to 1988 part. I was shocked when I found that the two lines from the master cylinder were "supply" and "return". On the 1988 the four corners are actually three, "front right", "front left" and "Rear". What I found most disturbing was the minute I had a leak in the brake lines that the pedal went to the floor and would not pump up or anything. I thought cars after 1964 were supposed to have two reservoirs to allow either the front or rear brakes to leak or fail without loosing your brake pedal completely. Not so on my car, one little leak and bang the whole system goes away. For this reason alone I will always have a very functional e-brake, this is one place where it is good to have the 1988 over the 1987 and earlier models.
Agreed. A relative has an 86 Vette and if I remember correctly, that only had one break reservoir.
We have a modern emergency brake that works great, no more little stainless brake shoes for the e-brake.
In my 74 Corvette, that was a major pain in the a$$ to access and change out the parking brakes! In that car, I put in all new bushings on the rear end, bearings, seals, and u-joints on the half shafts. A very crappy design to say the least! I got rained out today so, I have not had an opportunity to screw around and determine why the center dash display is lit up "BRAKES". It wasn't lit up when I took the car around the block. I possibly, have to take it out on the highway with little traffic present and get the rust off the rotors although, I would think that the rust would provide more friction. In the past few months, I have removed all the window tint on the vehicle including the back glass which was a major bitch, replaced an inner door window regulator, outer window weather strips on the doors, front hood lift pistons, back glass lift pistons, weather stripping around the front windshield, and all weather stripping for the one piece removable top. I am losing interest in this car very quickly!
I oil the cables every year and oil the mechanism and the E-brake works great. I was dissapointed to find that my daughters 2011 Camaro has the little brake shoes type E-brake. They do not hold as well in my opinion, I have that system on my 1968 C3 but made it work as best I could, It holds the car.
I tested mine out the other day when I encountered the brake light being lit on my dash and it appears to hold very well. Now I've got to figure out why that damn light is on and I don't think it is a sticking parking brake switch.
While working on my car I found the lateral acceleration sensor had broken loose at some point. I re-secured it in the original position and now I am anxious to see if there is any difference.
I use a Phoenix Systems "reverse brake bleeder" and that puppy really helps with the ABS unit getting bled properly and thoroughly. A very useful tool, it makes bleeding brakes a cinch, it also is a life saver trying to bleed a GM hydraulic clutch master cylinder. It is so simple now that I bleed the brakes every five years (at least) on every car and motorcycle that I own. This is one of the few tools that has made Corvette ownership easier if you do your own work.
I used to use a Mighty-Vac to bleed my brakes until I switched over to speed-bleeders. I was very skeptical about those since I can't see the fluid going into a clear mason jar to determine when the bubbles have ceased and the air is out of the lines. They seem to work well and the whole system bled out very well.
Good luck with getting your car back on the road with the stopping power Corvettes are known for!
If I can get my brakes back to what my 1981 had, I would be happy.
Last edited by Da Mail Man; 07-25-2018 at 10:57 AM.
07-25-2018, 11:11 AM
#23
Safety Car
Thread Starter
UPDATE (on brake light being lit on dash);
The brakes have seemingly improved quite a bit...Could have been the rust(?).....I do have the brake light lit up on the dash.
I read another thread about someone having the same problem......What was suggested and what I did was to unplug the brake light wire connector from the master cylinder (mc) and unscrew the switch itself....At the bottom of the switch hole is a smaller hole to which slides horizontally, the equivalent of an upside down hour glass and to which the center section of that "switch" is to be positioned directly beneath the bore bole...If there is a PRESSURE DIFFERENCE between the 2 brake "circuits", it will cause that "hourglass switch" to move laterally, make contact with the "pintle" of the brake light switch, short to ground ,and turn on dash light.
I inserted a stout pick and slid the switch over to re-center it....I then reconnected the brake light assembly and hit the brakes and it did it again!...I again re-set the switch but, this time I left out the switch and inserted the pick...I hit the brakes and the picked moved indicating that It did it again!...$#^^^*%^&!....I had a conversation with the parts guy whom seems to be familiar and he is leaning towards the mc being defective....Another day more aggravation!...I have another mc (used) that leaks at the rear seal and I just may try to TEMPORARILY put it on to see if that faults.....It did NOT trigger when I had it on or took it off.
The brakes have seemingly improved quite a bit...Could have been the rust(?).....I do have the brake light lit up on the dash.
I read another thread about someone having the same problem......What was suggested and what I did was to unplug the brake light wire connector from the master cylinder (mc) and unscrew the switch itself....At the bottom of the switch hole is a smaller hole to which slides horizontally, the equivalent of an upside down hour glass and to which the center section of that "switch" is to be positioned directly beneath the bore bole...If there is a PRESSURE DIFFERENCE between the 2 brake "circuits", it will cause that "hourglass switch" to move laterally, make contact with the "pintle" of the brake light switch, short to ground ,and turn on dash light.
I inserted a stout pick and slid the switch over to re-center it....I then reconnected the brake light assembly and hit the brakes and it did it again!...I again re-set the switch but, this time I left out the switch and inserted the pick...I hit the brakes and the picked moved indicating that It did it again!...$#^^^*%^&!....I had a conversation with the parts guy whom seems to be familiar and he is leaning towards the mc being defective....Another day more aggravation!...I have another mc (used) that leaks at the rear seal and I just may try to TEMPORARILY put it on to see if that faults.....It did NOT trigger when I had it on or took it off.
07-25-2018, 11:33 AM
#25
Safety Car
Thread Starter