I just installed a Wilwood 15/16" bore master cylinder and adjustable proportional valve on my 1972 Nova. It has 4 wheel discs on it without a vacuum booster. The rod is connected in the top hole of the brake pedal. I bled the master cylinder before hooking the brake lines. So far, I believe that I have done everything correctly. I have bled the brakes three times but the pedal keeps going down. I test drove it but it will not come close to stopping properly. What could I have done wrong? I'm stumped!
Spongy brake after installing Wilwood master cylinder
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how did you bleed them
when I changed my 63 to front disc and added a tandem master (no booster) , I bled so many times and just could not get the pedal pressure to increase
bought what I have always wanted in a bleeder that pressurizes at the master....not trying to suck at the wheel
did all wheels again was getting bubbles for quite a while
brakes have been great since
when I changed my 63 to front disc and added a tandem master (no booster) , I bled so many times and just could not get the pedal pressure to increase
bought what I have always wanted in a bleeder that pressurizes at the master....not trying to suck at the wheel
did all wheels again was getting bubbles for quite a while
brakes have been great since
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2,512 Posts
Air or possible bad MC or the wrong size bore? ..you have the caliper bleeders on the top i would call Wilwood support they should be able to help
I have a Phoenix Reveres inject bleeder tool not cheap but pushes fluid from wheel to master works great, they make a cheaper version
![Product Wheel Gas Motor vehicle Font]()
I have a Phoenix Reveres inject bleeder tool not cheap but pushes fluid from wheel to master works great, they make a cheaper version
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857 Posts
I bought the economy reverse bleeder from NAPA. Works the same but much cheaper.
Pressure Brake Bleeding Systems
Pressure Brake Bleeding Systems
. Turns out that my Wilwood master cylinder had a recall on it and was faulty from new. I bought a new one and it worked much better. Bleed them good and let them sit for a few days. While in the shop every once in a while pump them up. It would be great if you could actually move the car around a little bit. Eventually if there is air it will gravitate towards the calipers allowing you to bleed it out. May take a few times but eventually it will come out.
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4,551 Posts
Who makes the brake calipers? If wilwood are you bleeding the top caliper bleeder screw?
Sometimes chasing air in the system I will clamp the rear rubber brake hose to see if the soft pedal is coming from the front.
keep us posted. I do recall wilwood having a recall on one of the MC’s I had to send back to be addressed- don’t know if mine actually had a problem.
Sometimes chasing air in the system I will clamp the rear rubber brake hose to see if the soft pedal is coming from the front.
keep us posted. I do recall wilwood having a recall on one of the MC’s I had to send back to be addressed- don’t know if mine actually had a problem.
Thank you for this info!!!
Thanks to all who have replied. I called Wilwood today, for the 3rd time. A little history first. I called them the first time and was told to get their 1-1/8" master cylinder. I tried installing it but had a few issues getting the correct rod length. Called them again, 2nd time, and was told I have the incorrect master cylinder and I need a 7/8" or 15/16" bore. So, I bought a 15/16 and installed it. That leads us to now, where I can't get a good pedal. I called Wilwood today and was told, once again, that I have the wrong master cylinder and I need a 1-1/8". I was quite aggravated, as you can imagine. The company I purchased from is trying to help me with my situation, thank goodness. My question to everyone is, what's the right master cylinder and what would you do from here?
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451 Posts
2 things, as a young man, many moons ago, i had the front calipers reversed, the bleeders were on the down side, duh! and, i always bench bleed the master cylinder, ok, then i have gravity bled , always worked for me. takes a few days.
I have same set up on my 63, I bleed with air , to each brake cylinder, had off and on many times, never no issues, I think I go over your system again, and tighten, and re tighten again, good luck, bet its simply and out of frustration your over looking it, good luck
They are a factory type of caliper. All the bleeders are "up". Good idea on clamping the lines to evaluate. I will try that. Thanks!
Bleeders are in the "up" position. They are factory calipers. I will try to bleed again and see what happens. I think I have the correct master cylinder?! Thanks for replying!
Thanks! Will try bleeding again. If still spongy, I will purchase one of the force fed bleeding systems everyone is talking about.
Yes, Wilwood knows they are manual brakes. A big part of my concern is the different recommendations. Makes me wonder about their sales staff competence on the product. The last conversation with them was this 15/16" MC is creating a spongy pedal. Seems like many others run this size without an issue. I'm waiting to hear from one of their sales reps now.
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