Master Cyl Failure

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Nov 27, 2007 | 01:49 PM

tee-boy

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Master Cyl Failure

what is the number one reason a MC fails? Is it basically the seal erodes/corrodes and therefore it no longer effectively forces fluid into the stainless line? Or is it maybe the return spring that fails? Or is it maybe the lines get clogged w/ solid material and therefore no fluid movement?

Nov 27, 2007 | 04:14 PM

JonB

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A combination of things, condensation(aka water in the system), deteriated fluid, air in the system, normal wear and tear. On your car which I get from your sig is a 98 that means that master is 10 years old now. How many times in 10 years has that pedal been depressed? I'm gonna guess in the millions over 10 years. The o-rings inside the master rub inside twice every time you depress and let the pedal back up. Although they are lubed with brake fluid over years of use they will eventually wear causing problems after all they are only rubber.

Now if you've changed your master a few times already and looking for a solution I would look into keeping your fluid clean and fresh and air free.

Nov 27, 2007 | 06:54 PM

tee-boy

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ddd

cool, but what is the number one reason for failure... Spring, Seal, Clogged ports?

Nov 28, 2007 | 12:40 AM

TARZAN

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My guess would be (if you had to choose ONE thing) worn out fluid.

-Will

Nov 28, 2007 | 07:23 AM

tee-boy

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ddd

Quote:

Originally Posted by TARZAN

My guess would be (if you had to choose ONE thing) worn out fluid.

-Will

worn out fluid is not a failure! Worn out fluid is a cause of a failure.

Nov 28, 2007 | 07:37 AM

brad8266

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The primary reason for master cylinder failure is pitting/deterioration of the bore surface in the cylinder, which leads to the internal seals tearing on the pits edges as they travel across the pits. This is accelerated by old worn fluid and moisture in the fluid.