Just replaced all four calipers...front two were a bit leaky. I started bleeding the brakes but am not getting much of anything out of the rears. By the way, my brakes felt fine before replacing the calipers. My question is this...my fluid level in my master cylinder went to practically nothing when I took my old calipers off, so do I need to bench bleed the master cylinder or can I just do the correct bleeding order and get good brakes? I think I probably just have a lot of air in my lines and need to bleed them properly. My thought was it was probably air and not a bad MC since they were fine before I removed the calipers. Any thoughts? Thanks.
Ward

 

Vette brakes are a PITA. Even a little air bubble can be problems and hard to get out without using a power bleeder. I'd first try to find one. If not try the following two person procedure(assumes your Vette can follow the procedure for a 79).

Bleed each break in the following sequence:
1) Passenger side rear - top
2) Passenger side rear - bottom
3) Driver side rear - top
4) Driver side rear - bottom
5) Passenger side front
6) Driver side front

For each break, have a buddy pump the petal. If the buddy can't feel any pressure, pump 5 or 6 times and hold to the floor. If he can feel pressure, pump 3 times and hold to the floor. Unsrew the bleeder and let out air. Retighten bleeder. Repeat pumping and bleeding until a solid stream of fluid comes out. Go to next bleeder.

You may have to repeat the entire sequence several times to get out all the air. It may also help to let the car sit all night between sequences.

Best of luck.

 

I use a hand hel vaccum pump to bleed my brakes, as ffor the rear's
I use a split hose, like a Y to bleed both valve in the rear calipers.
I find this to be the best method for bleeding the rear.

 

I just replaced all of my wife's 77's calipers and master. So I know what you're saying about getting nothing from the back.

I bet your pedal goes all the way to the floor and the brake warning indicater is lit up, right? The problem I had was with the "proportioning valve" doing it's job. There is a slider that moves with the brake fluid and seals off either the front or rear when a mismatch of flow occurs. It's designed this way to give you some amount of braking ability even if you blow a brake hose. It isolates the front or rear depending on where it thinks that there is a failure. If you get too much air in the lines, the air will compress when you pump the pedal. More fluid flows through the valve before pressure builds up. The isolater kicks in and shuts off the flow going to the end of the car with air in the lines. SO..... Hopefully the valve isn't jammed in one direction now. You should be able to reset it by firmly grasping the steering wheel and smahing down the brake pedal a few times like it is a rattlesnake trying to bite you. (This is what I found from searching right here in the C3 forum.) This usually will free up the valve and return it to the neutral position allowing you to get more fluid (and air) from the lines. Be sure to press the pedal down SLOWLY while bleeding the brakes or you'll have the same problem once again. Be sure to bleed from all of the bleed screws in the back. Mine had 3.

After doing this my brakes work like new again.

 

I just rebuilt my front calipers, and I had to do the pump, hold, bleed thing close to 15-20 times before I got a good stream of brake fluid. Most of the time, I didn't get any air or fluid. I just figured eventually it would work, and it did..

 

After bleeding my brakes for about an hour they finally produced a nice air free streem to my rears. All seems well again. Thanks,
Ward