Need help resetting a combination valve??
Thread Starter
Pro
Joined: Jun 2004
Posts: 700
Likes: 0
From: Lantana TX
The master has also been bleed 4 times to make sure.
Pedal is hard as a rock with the car off, but when I start it up it almost goes to the floor. Driving and stopping is slow but it will come to a stop eventually....
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
The one thing I don't see is either a rebuild of your master cylinder or a replacement. In my world, a pedal that goes to the floor means a failed MC. Is yours original, rebuilt, or???
Thread Starter
Pro
Joined: Jun 2004
Posts: 700
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From: Lantana TX
New master (Wilwood aluminum tandem 1 1/8 size). The rod has no travel when the MC is put on. Meaning it is not pushing on the bore nor is there any space between the rod and the bore itself. How do you know if it is too short, but hiting the bore when installing?
I agree and thought it was the MC, maybe air was escaping or getting by.However, I tested the MC by blocking off the ports and got a very hard pedal with no movement while applying pressure with the car off and with the car running, and no travel was evident.
I agree and thought it was the MC, maybe air was escaping or getting by.However, I tested the MC by blocking off the ports and got a very hard pedal with no movement while applying pressure with the car off and with the car running, and no travel was evident.
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Instructor
Joined: Feb 2006
Posts: 229
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From: Crestview Fl
After mine set up for a couple of months with the rear calipers off, I had
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
Thread Starter
Pro
Joined: Jun 2004
Posts: 700
Likes: 0
From: Lantana TX
After mine set up for a couple of months with the rear calipers off, I had
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
I am thinking it is the prop valve going to the rear. I pluged up the front from the MC turned on the car and the pedal slowly went to the floor. I did the opposite and the front stayed hard, which is why I am thinking it is the prop valve. Maybe it is stuck and the reason why I wanted to se if there wa a way to reposition it.
Racer
Joined: Aug 1999
Posts: 466
Likes: 71
From: West Chester PA
After mine set up for a couple of months with the rear calipers off, I had
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
a heck of a time. If your's has the proportioning valve you need to verify the calipers are getting pressure. My fronts were good but with both lines on the rear loose no fluid would go to the rear,on mine I buckled the rear back up and bled the front untill the valve re-centered.
That's all it took after a gallon of fluid. Terry
www.classicchevy.com-assets-pdf-brake_guide.pdf
www.classicchevy.com/assets/pdf/brake_guide.pdf
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
I am sooooo stumped by this and no matter who I ask, nobody can figure it out. Yes, I have fluid coming out of the rears with no issues. I can gravity bleed them all I have also replaced all the rubber lines.
I am thinking it is the prop valve going to the rear. I pluged up the front from the MC turned on the car and the pedal slowly went to the floor. I did the opposite and the front stayed hard, which is why I am thinking it is the prop valve. Maybe it is stuck and the reason why I wanted to se if there wa a way to reposition it.
I am thinking it is the prop valve going to the rear. I pluged up the front from the MC turned on the car and the pedal slowly went to the floor. I did the opposite and the front stayed hard, which is why I am thinking it is the prop valve. Maybe it is stuck and the reason why I wanted to se if there wa a way to reposition it.
Is your dash warning light illuminated?
One way to ensure the combination/proportioning valve is good is to replace it.
Former Vendor
Joined: Nov 2005
Posts: 683
Likes: 1
From: Mounds View Minnesota
The above comment make me think you have a bad MC. The rear circuit is leaky. I know you have a new MC but still...
Thread Starter
Pro
Joined: Jun 2004
Posts: 700
Likes: 0
From: Lantana TX
I hope that helps better explain things.
Thread Starter
Pro
Joined: Jun 2004
Posts: 700
Likes: 0
From: Lantana TX
I keep buying components that are not fixing the solution, which is why I am trying to find a way to test the P valve.
Is there a way to take it apart and clean it maybe?
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
I have bleed them sooooo many times I just cannot believe that air would still be trapped. Seriously, I have bleed them at least 6-7 times and each time I push almost a qt through the lines while tapping on the calp. I started off gravity bleeding, I then switched to speed bleeders, which worked well, then finally I bought the Motive bleeder again worked well.
I keep buying components that are not fixing the solution, which is why I am trying to find a way to test the P valve.
Is there a way to take it apart and clean it maybe?
I keep buying components that are not fixing the solution, which is why I am trying to find a way to test the P valve.
Is there a way to take it apart and clean it maybe?
ZIP has a detailed write-up on the brakes; http://www.corvettemagazine.com/content/view/85/, with a procedure for bleeding. (Note what it says in regards to jacking up the rear of the car in order to bleed the system)
It tells how to bench bleed the master and how to bleed the brakes. If you have not done them as described, you should carry out the suggested method.
I would think that if you do not have a brake warning light illuminated on the dash, then your proportioning/combination valve is not the issue. Typically, it is not a rebuild item. Replace with new, if faulty.
You can check the warning switch operation, by grounding the contact which should illuminate the warning light on the dash. If the warning light is extinguished with power on the vehicle and lights up under test condition then your valve is not the issue.
Burning Brakes
Joined: Feb 2005
Posts: 1,235
Likes: 0
From: Mesa AZ
even if the proportioning valve was bad that doesn't give a reason why the pedal would go to the floor. the brakes are a closed system . it doesn't matter what goes to front or rear there will always be pressure and a hard pedal.
am i totally wrong here or what?
am i totally wrong here or what?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Strategically, you should now consider a defective component which you have recently replaced. It is natural to assume that new parts are "good"....when, in fact, a significant percentage of new parts do not perform as intended. Re-check the integrity of every part which you have changed but has only been operational as part of your malfunctioning system. It could be a "new" hose with a bad crimp on a fitting....a porous casting which is not leaking fluid, but can suck air...a mismachined part (as in a M/C valve which is not sized or shaped correctly)...etc, etc. Good luck.