 Brake pedal randomly goes to floor |
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| tornik550 |
 May 24 2012, 04:51 PM
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#1
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Senior Member  Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None  |
I have not driven my car for a few years due to my engine rebuild. I bled my brakes. The brake pedal was hard when pressed however over the next day or so the pedal would creep down very slightly at red lights. I bled the brakes again however it did not help the problem. Now at stop lights sometimes the pedal is hard, sometimes it creeps all the way to the floor. Normally if the pedal starts to creep down, if I let off and reapply the brake, it will be firm- at least for a while.
-Does this sound like a master cylinder problem? -I have searched and I do not see any brake fluid leaks. -the brakes have been bled -I am using stock 914-4 calipers with porterfield pads - the rears have been properly clearanced |
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| Dave_Darling |
May 24 2012, 05:28 PM
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#2
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914 Idiot Group: Members Posts: 15,196 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California 
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On my old Hondas, this exact thing was a symptom of a bad master cylinder. Replacing the MC cured it in both cases.
--DD |
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| TheCabinetmaker |
May 24 2012, 05:50 PM
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#3
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I drive my car everyday Group: Members Posts: 8,338 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
Yep. Master is bleeding internally
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| avidfanjpl |
May 24 2012, 05:57 PM
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#4
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914 Hemophiliac Group: Members Posts: 720 Joined: 6-April 10 From: Bear, Delaware Member No.: 11,566 Region Association: MidAtlantic Region |
Yes, I had one leak on a car. Replace it with the 19MM, and the brakes feel better.
Lots go round and round on 17MM vs. 19MM I have used both. Go with the 19MM and make sure you get new switches, at the pedal and in the MC. MC usually comes with that switch installed. One on the brakes is a separate part. John |
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| tornik550 |
May 24 2012, 06:58 PM
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#5
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
I just got under the car and took out my master cylinder. I never really knew if I had a 19mm or a 17mm MC. My car was modified for autox when I purchased it. The MC only has three marks- ATE 19 and 16. Am I correct in assuming that my MC is a 19mm MC? Also, taking cost into consideration- which is best- rebuild or buy a new one?
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| mepstein |
May 24 2012, 07:21 PM
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#6
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914-6 GT in waiting Group: Members Posts: 19,954 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region
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Mine hit the floor today backing out of the garage. Will take a look in the AM. If the master is bad, Eric Shea will be getting a call. I will probably send him my calipers as well. Rebuilt calipers - yes, rebuilt master - no. I like the 17mm. Little less firm, little more power.
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