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Hydraulic Brake Question (basic)

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Hydraulic Brake Question (basic)

Old 09-24-13, 07:23 PM
  #1  
TakingMyTime
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Hydraulic Brake Question (basic)

Is there any kind of failsafe or backup if you lose fluid for one reason or another?

Just wonderin'
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Old 09-24-13, 07:39 PM
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The front and rear brakes are completely separate systems so you're unlikely to lose both at the same time.

There's no fail safe if you brake a cable either.
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Old 09-24-13, 08:02 PM
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Yes, same as with cable brakes, or car/truck brakes or even critical systems in aircraft, safety is based on redundancy. Two independent systems, so in the event of total failure of one you still have the other.
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Old 09-25-13, 05:49 AM
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In older Citroen cars the hydraulics powered the gearchange, suspension, steering and brakes. In the event of loss of the pump there was a small reservoir called the accumulator. With pump failure the dashboard warning lights would light up like a christmas tree and, in order, the car would give up on gearchange, suspension, steering assist and very last of all - brakes.

After that you could only slow down by running over some cyclists.
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Old 09-25-13, 07:46 AM
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Originally Posted by jolly_ross View Post
In older Citroen cars the hydraulics powered the gearchange, suspension, steering and brakes. In the event of loss of the pump there was a small reservoir called the accumulator. With pump failure the dashboard warning lights would light up like a christmas tree and, in order, the car would give up on gearchange, suspension, steering assist and very last of all - brakes.

After that you could only slow down by running over some cyclists.

This is just one of the many reasons Citroen has come to dominate the world automotive market.
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Old 09-25-13, 08:02 AM
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for the young readers,from the 'Duck and Cover' student generation:

Fail Safe, a 1964 film. [from Imdb]

American planes are sent to deliver a nuclear attack on Moscow,
but it's a mistake due to an electrical malfunction. Can all-out war be averted?

A series of human and computer errors sends a squadron of American 'Vindicator' bombers to nuke Moscow.
The President, in order to convince the Soviets that this is a mistake,
orders the Strategic Air Command to help the Soviets stop them.
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Old 09-25-13, 08:10 AM
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Originally Posted by Retro Grouch View Post
There's no fail safe if you brake a cable either.
Understood. I was just wondering if along with the Hydraulic setup there was any sort of backup "built in".
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Old 09-25-13, 08:59 AM
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dragging your feet on the pavement ..
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Old 09-25-13, 09:11 AM
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Originally Posted by TakingMyTime View Post
Understood. I was just wondering if along with the Hydraulic setup there was any sort of backup "built in".
No, just like cable brakes, bicycle brakes are normally open, (aka fail open). That means they're designed to stay open if there's a mechanical failure of any kind. This is opposite to the arrangement of air brakes on trains and heavy vehicles like trucks and buses. Those are normally on, and the air system the driver operates keeps them off. If the air line is cut, the brake goes on. That's why you often hear the compressor running to build up pressure before they start out.

You wouldn't want a fail-on brake on a bike because if the line were cut the front brake would lock up and you'd do an endo.
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Last edited by FBinNY; 09-25-13 at 09:25 AM.
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Old 09-25-13, 09:27 AM
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Originally Posted by Looigi View Post
This is just one of the many reasons Citroen has come to dominate the world automotive market.
That and their stellar reliability.
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Old 09-25-13, 09:29 AM
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Originally Posted by TakingMyTime View Post
Is there any kind of failsafe or backup if you lose fluid for one reason or another?

Just wonderin'
Running into something soft

Like others have said, it's just as fail proof as a cable brake.

I have hydro discs on my Giant Roam 2 and love them. While I realize that they are completely unnecessary and overkill for the type of biking I do I do sure like them! They are very smooth, the brake lever is smaller, takes less pressure and seems to have finer control than my old bikes V brakes. They are well worth the extra $$$ I spent, at least I realize I have spent more for other things that I have enjoyed far less than these bakes.
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Old 09-25-13, 09:30 AM
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Originally Posted by FBinNY View Post
You wouldn't want a fail-on brake on a bike because if the line were cut the front brake would lock up and you'd do an endo.
Also I think such brakes are quite difficult to modulate.
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Old 09-25-13, 09:33 AM
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Being on top of your maintenance is the key . if you see hose damage, you replace it. before it breaks open ..
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