Help! Master cylinder:

[Crimson Thunder]

You could always start off bench bleeding it in a vise and then when the piston gets hard to push with a screwdriver install it on the car and finish with the brake pedal. The last master cylinder I installed took about 30 minutes of bench bleeding to get all the air out.(genuine AC Delco Made in Chinaad)

 

[401KVet]

Hissing noise:

Not really having the time to mess with the brakes today, I still went outside and cranked her up to idle for a while. At least get the oil hot and circulate. The car has not been driven for some time. While idling, I got my small shop air compressor out to put air in the tires. I had gauged them and they were all a little low. After that I rolled the compressor to the shed door and opened the valve to let the air out of the tank before putting it up. It's a small compressor so it doesn't take but about 5 seconds or so to empty, and you know what kind of noise that makes. I'm inside my shed, the Vette's right outside idling, just on the other side of the shed wall, and I could have swore I heard another swishing noise like the air coming out of the compressor. About 10 seconds after the compressor emptied. It had to have come from the car, which was still idling. I looked the booster over real quick and didn't see anything out of the ordinary. I had to call it quits for the day then and now. Mother's Day. Anyhow, does anyone have any thoughts on the noise that I think I heard???

 

[401KVet]

Still trying:

Ok, I found out that the check valve in booster was bad. Replaced it and the brake pedal went from being very hard to soft and spongy. I then did a so called bench bleed with a kit I bought from Napa, but I did it on the car. Pressing down slow and releasing the brake pedal slow for almost 1 hour. The rear of the MC took for ever before I had no bubbles coming from it. I then power bled using the Motive power bleeder. The pedal was a little better but not great. I power bled all 4 once more. Still not so great. You can drive the car and it has brakes, but nothing that would be good for a really quick stop. At this point I think the MC is bad.?? Before calling it I would like to do a gravity bleed, and then a power bleed once more. Could anyone give me the steps for doing a gravity bleed... Does the fronts have to be higher than the back for gravity to work on the rear, and the same for doing the front? The rear being higher?? Do you do all at one time?? Thanks..