HELP: 67 Camaro brake problem

Hi Gentlemen and ladies,
Problem I am experiencing is there is little pressure in my brake system making it difficult to bleed the brakes, and of course, no
brakes.
I originally powerbled the brakes but did not push the "button" on the proportioning valve. In fact, I think the proportining valve is stuck in the depressed position. How and does this affect the brake system? Will powerbleeding the system without pushing the button on the proportioning valve hurt the system?
I have replaced the master cyclinder already and bled the system manually by having someone depress the brake foot pedal in the "old fashioned way".
What am I missing? Or is the poroprtioning valve just bad causing all this havoc?
Thanks!
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On Sun, 01 Feb 2004 02:15:51 GMT, ULB

One thing you might want to consider is the age of the flexable lines that run to the front brakes and the one at the rear. The rubber deteriorates over time and will collapse internally thus allowing little pressure to reach the brake cylinders. I don't know what button you are talking about that would be placed on the proportioning valve, mine (68') has a loss of pressure sensor on it with a wire going to the idiot light. One other thing to think about is that there might be rust in the lines causing a restriction.
The proportioning valve should not have any way to change the rate of flow through it unless it has a regulator on it like you find in aftermarket units. The valve itself just allows more fluid to flow to the front brakes through small holes called orifices, the one for the front being larger than the one for the rear.
...ron -- 68' RS Camaro 88' Formula Bird
http://www.frontiernet.net/~rscamero
Some are wise and some are otherwise
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According to my Wagner Brake Bleeding Sequence Guide from July of 1993.When Pressure Bleeding Bleed fronts first, together, then rears, togher. Manuial bleeding recommended. Bleeding Pressure 20-30 PSI. Manuial Bleeding: Right Rear, Left Rear, Right Front, Left Front.
It does not mention the proportioning valve. It is possible the bypass is stuck. You can try lightly tapping it with a hammer. If not it may need repalced. Charles
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I have the same problem with my '67. I started out by power bleeding the system but didn't know I was supposed to hold in the metering valve. This is the thanks I get for using the Mytivac. It never would depress. In my case I've replaced the master cylinder twice and bench bleed it so there are no bubbles. I've even power bled it. When I plug the master cylinder outlets the piston feels very hard, just like it should. However, when you bleed the system the power of the master cylinder does not seem to hold up. My metering valve does not depress either and seems stuck in the depressed position. I wonder if this is the entire problem? I'm going to get a new one from Ricks and give it a try. This is so maddening I'm thinking of tourching the car...just kidding.
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