 Potential Brake Failure?, Loss of brake pedal position |
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| rbzymek |
 Jul 23 2026, 02:14 PM
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#1
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Member  Group: Members Posts: 203 Joined: 5-April 19 From: Northville, MI Member No.: 23,013 Region Association: Upper MidWest 
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I was hoping for some direction to correct a brake issue. While driving last week my right foot was resting on the brake pedal and then it started moving down! The brakes still worked but the pedal was way lower than design position. I pulled over immediately and had the car towed home. I installed a new master cylinder 7 years ago (about 13,000 miles) from 914Rubber (not uro). All four corners were rebuilt by PMB. New flex hoses and pads were also installed. Brakes have been working fine prior to this hiccup. Fluid resevior was full and no leaks detected.
So I suspect the M/C but are there any other possibilities? Thanks in advance! |
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| bkrantz |
Jul 23 2026, 07:48 PM
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#2
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914 Guru Group: Members Posts: 8,741 Joined: 3-August 19 From: SW Colorado Member No.: 23,343 Region Association: Rocky Mountains
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If truly no leaks and no fluid loss it might likely be a problem in the MC.
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| emerygt350 |
Jul 23 2026, 08:06 PM
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#3
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Advanced Member Group: Members Posts: 3,676 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
The only other thing would be a sudden change in the rear brake adjusters which seems impossible.... What happens when you pull the parking brake? Does the pedal travel decrease?
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| rbzymek |
Jul 24 2026, 09:24 AM
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#4
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Member Group: Members Posts: 203 Joined: 5-April 19 From: Northville, MI Member No.: 23,013 Region Association: Upper MidWest
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QUOTE(emerygt350 @ Jul 23 2026, 10:06 PM)  The only other thing would be a sudden change in the rear brake adjusters which seems impossible.... What happens when you pull the parking brake? Does the pedal travel decrease? The hand brake has no affect. It behaves normally as far as pedal travel. I plan to bleed the system and watch it closely. |
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| flipb |
Jul 24 2026, 09:41 AM
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#5
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Senior Member Group: Members Posts: 1,886 Joined: 2-September 09 From: Fairfax, VA Member No.: 10,752 Region Association: MidAtlantic Region
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The MC mounts to relatively thin metal that is known to fatigue over time. Maybe you punched the MC off its mounting point.
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| Ninja |
Jul 24 2026, 10:29 AM
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#6
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Member Group: Members Posts: 251 Joined: 25-September 25 From: Granbury Texas Member No.: 29,004 Region Association: Southwest Region |
Any aftermarket master cylinder is suspect...
914 rubber did not make the cylinders themselves (I believe). They subbed the work out. Try to find an ATE master. They have gotten expensive. I own an auto repair shop and I DON'T install anything but OEM master cylinders. If it's discontinued (happens a lot on 15+ year old cars) I decline the job now-a-days. |
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| brant |
Jul 24 2026, 10:44 AM
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#7
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914 Wizard Group: Members Posts: 12,235 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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Did you pull the pedal board and then pull the rubber boot on the plunger
That’s where the leak is usually |
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