Another Master Cylinder Question
Thread Starter
Instructor
Joined: Jan 2011
Posts: 146
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From: Hillsborough NC
Another Master Cylinder Question
What would be the problem in retaining a 1" bore master cylinder (from a manual brake setup) for use in a vacuum boosted power brake setup? Would it just be overly sensitive when compared to the recommended 1 1/8" bore?
Thanks,
AL
Thanks,
AL
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If I'm not mistaken the depth of the pushrod hole is a lot different also. The manual one is deep.
JIM
JIM
Race Director
Joined: May 2006
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From: Dayton, Ohio
I would think a 1" with a booster would make the pedal too sensitive but the pedal might have a tendency to go to the floor,because I believe the 1" travels more than the 1 1/8".
Thread Starter
Instructor
Joined: Jan 2011
Posts: 146
Likes: 2
From: Hillsborough NC
Thanks all for your responses.
I hadn't considered the depth of the push-rod hole. I was also considering keeping it a manual and going to a 7/8" MC, but after hearing about the increased pedal travel, I think I have ruled that out.
My 73 currently stops almost okay but will not lock up the wheels at all and does seem to have a long pedal travel. Could tire size impact the ability to lock up the wheels? Mine are 215/70/R15 and 255/60/R15.
I hadn't considered the depth of the push-rod hole. I was also considering keeping it a manual and going to a 7/8" MC, but after hearing about the increased pedal travel, I think I have ruled that out.
My 73 currently stops almost okay but will not lock up the wheels at all and does seem to have a long pedal travel. Could tire size impact the ability to lock up the wheels? Mine are 215/70/R15 and 255/60/R15.
Drifting
Joined: Mar 2011
Posts: 1,886
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One of the advantages of a power brake system is that the pedal travel is reduced. The larger bore of the power brake master cylinder moves more brake fluid per inch of pedal travel than the non power cylinder. A panic stop with power brakes might require only two inches of pedal travel, while a manual brake could require four inches, for example.
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Thread Starter
Instructor
Joined: Jan 2011
Posts: 146
Likes: 2
From: Hillsborough NC
bench bleed
That's what I thought too after reading about a dozen threads on bleeding.
I have bench bled (at a 45 degree angle), and vacuum bled, and power bled, and standard bled what must have amounted to 3-4 gallons of fluid by now.
No bubbles for the last several times I have bled it. I just can't believe there is still trapped air unless my rotors are way, way off since I have the o-ring calipers.
Am I supposed to be able to lock up the brakes?
I have bench bled (at a 45 degree angle), and vacuum bled, and power bled, and standard bled what must have amounted to 3-4 gallons of fluid by now.
No bubbles for the last several times I have bled it. I just can't believe there is still trapped air unless my rotors are way, way off since I have the o-ring calipers.Am I supposed to be able to lock up the brakes?
Burning Brakes
Joined: Aug 2005
Posts: 801
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Yes.Im still fighting air in mine with dot 5 fluid.Even then my brakes will lock up and stop on a dime.Just a little too much pedal travel for my tastes.I'm going to bleed them some more.I converted to power brakes and o ring calibers.Good luck and hang in there.
Race Director
Joined: May 2006
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From: Dayton, Ohio
I put my dot5 in a sauce pan and heat it up to around 250 degrees,let it cool and then put it in the car,pedal is less spongy.