Brake issues

I have a 1979 Vette and I have an issue with the brakes. At one time I had brakes and I had all new pads put on as I was having the entire car serviced. I put a new left front caliper on and I had good brakes
for about two to three months. I drove the car to Virginia to put it in my families garage as I was getting deployed to Iraq for one year. As I was driving the car to Virginia about 200 miles into the trip I went to pull off and get gas when the brakes failed s the pedal went to the floor. After my deployment I brought it back home, in DE, where I replaced the master cylinder, and the left front caliper and I bled all the brakes and bench bled the master cylinder and I still am unable to get pedal. All calipers are expelling fluid as I bleed them and I realize that there are 2 bleeders in the rear calipers. I am having issues with the fluid coming out of the new caliper but the flex hose has fluid coming out before I put it on the caliper and I can not get any pedal at all. The brake light continues to stay on and I checked to see if I had a bad booster but it seems to be alright as I removed the hose and there is suction and the the brakes get hard until I put the hose back on and the brakes go soft again. Can anyone help me with this issue? Any ideas? Thanks. Brian
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wrote:

Brian Have you had ALL the calibers checked..? I have a funny feeling you have one or more that are sucking air into the system.. and it is NOT at all uncommon especially if they sit unused for a short period of time...
Bob G. 64 72 & 98 Ragtops 76 & 79 Coupes
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On Jul 16, 7:37 pm, Bob G. <rg327_remove_comcast.net> wrote:

Sir, The only thing I did was pull off all of the wheels and look for leaks and I did not see any spots except for the one that I replaced. You are correct though, it seems that I can not get a solid steady stream of fluid without getting air pockets as it seems to be alright until I do it one more time to make sure all the air is out but it is really hard to tell if I did a good enough job bleeding the brakes. I can not seem to find any leaks but there must be something. I am not really sure what to do next as I am perplexed. I am very mechanically inclined but this is kicking my butt. Any suggestions on how to check the system for air leaks other than the obvious? Thanks for your help and info, it is much appreciated. Brian
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Hi Brian,
First, thanks for your service to our country.
Second, try writing in paragraphs, as it makes it a lot easier to follow what you are saying.
Third, Corvette brakes are notorious for going bad while sitting. Driving them all the time cures a lot of brake problems. However, once bad, they don't cure themselves.
If you have replaced the calipers with stainless steel sleeved calipers, then you have gone the first step.
How old are all the flex hoses? If they are unknown or more than a few years, replace them so we can start with a known good quantity. Hoses tend to come apart inside and look great outside, but they act like one-way valves and mess up the braking.
Replacing the master cylinder may have created a problem for you. The adjustment on the pushrod on the master cylinder from the booster is critical. It has to make contact when the MC is installed so that you do not have wasted motion in the depressing the pedal but it MUST NOT depress the piston at all as this begins to close the rear ports on the MC. This adjustment can take awhile to do, as you need to adjust so that you can slide the MC into position until you feel the rod contact the MC piston but you can still slide it all the way flush with the booster without the piston moving.
There are many ways to bleed the system, but my personal favorite is gravity bleeding. Put the car on jackstands, remove all four wheels, and begin.
Open a bleeder on the right rear and wait until fluid begins to run. Check for bubbles, and after you are sure it is clear, open the other bleeder on the same caliper. The bleeders are only on top. The lower end should have the brake line and a plug, although some people insert a bleed screw there.
Repeat this with the left.
Do the same on the front. You can do both ends at once, as they are separate circuits, however, a '79 uses a common reservoir so you have to watch that it doesn't go empty on you.
After new hoses, you may not get any fluid for a long time, as the lines are empty. For a fresh system or one that has been drained, and I don't want to wait all day and night, I start with the common old pump, pump, pump, bleed method.
Have a friend pump the pedal a few times, then crack open the bleeder. Be sure to close it before his foot hits the bottom. Repeat until you get fluid.
Then repeat this from each bleeder, starting right rear, left rear, right front, and left front.
Then go back and do the gravity bleed on the entire car.

I am

The brake light continues to stay on and

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I got interrupted on my last note and forgot all about the calipers.
If you have stainless steel sleeved calipers, then you may have to just put in a set of seals. You can get these from various brake places like Vette Brakes and Products, Stainless Steel Caliper Corp, Muskegon Brakes, and others for around $35 a set.
Unfortunately, the weak part is the pistons. They tend to corrode in the grooves where the seals go. You can sometimes clean these enough with a wire wheel to get them to seal, but depending on the age and the corrosion, you may have to replace pistons.
Most would tell you to trade your calipers in for a fresh set of SS sleeved calipers, but a set of SS sleeved are not cores and will not be accepted. So you are better off rebuilding your own if that is the case.
Good luck, it really sounds harder than it is.

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I think I would start at the new caliper, it may be defective. Look for blockage and leaks that seems to be when your problems started kickstart
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