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
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
What am I missing? Or is the poroprtioning valve just bad causing all
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.
68' RS Camaro
88' Formula Bird
Some are wise and some are otherwise
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
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
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