I've got that sinking feeling.

Post by **Donald** » Wed Jan 02, 2013 6:20 pm

Air and water are both fluids

mercutio · Post by **mercutio** » Wed Jan 02, 2013 6:51 pm

air isnt a fluid but water is compressable where hydraulic fluid isnt

Post by **Donald** » Wed Jan 02, 2013 7:01 pm

Air is a fluid but it's okay merc

anything is compressible, but I will concede in this situation I doubt you'll compress hydraulic fluid with your foot.

Here's one for the nerds: if hydraulic fluid was incompressible then the speed of sound within it would be infinite, or non existent?

mercutio · Post by **mercutio** » Wed Jan 02, 2013 7:03 pm

i get that air works or acts as a fluid for physics purposes

Post by **Donald** » Wed Jan 02, 2013 7:05 pm

No just in general merc

flu·id [floo-id]

noun
1. a substance, as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape.

adjective
2. pertaining to a substance that easily changes its shape; capable of flowing.
3. consisting of or pertaining to fluids.
4. changing readily; shifting; not fixed, stable, or rigid: fluid movements.

Physically, semantically, pedantically, air is a fluid.

Post by **Gayno** » Wed Jan 02, 2013 7:44 pm

Donald wrote:Here's one for the nerds: if hydraulic fluid was incompressible then the speed of sound within it would be infinite, or non existent?

It depends if the fluid is under pressure at the time, however I feel there will never be enough pressure in the fluid to stop all movement.

If the fluid is just sat in a container at air pressure, then the speed of sound through it would be the same as it is through any other liquid.

Post by **Donald** » Wed Jan 02, 2013 8:01 pm

Gayno wrote:
Donald wrote:Here's one for the nerds: if hydraulic fluid was incompressible then the speed of sound within it would be infinite, or non existent?
It depends if the fluid is under pressure at the time, however I feel there will never be enough pressure in the fluid to stop all movement.

If the fluid is just sat in a container at air pressure, then the speed of sound through it would be the same as it is through any other liquid.

The fluid isn't under any additional pressure, assume standard temperature and pressure, but an incompressible liquid, i.e. one of its properties is incompressibility.

Liquids have different densities and compressibility, so sound speed will be different for every liquid. Sound travels faster through paraffin than water, etc.

Maybe a mod can split this topic to somewhere else

Post by **Gayno** » Wed Jan 02, 2013 8:42 pm

I would if it was in the NSFW area

lxstuart · Post by **lxstuart** » Wed Jan 02, 2013 9:37 pm

From a physics point of view, air is a fluid and water isn't. Trololololol
Speed of sound in an incompressible liquid, I personally would treat it as a solid and calculate that way.

But, ahem, back to topic.

Standard hoses all round, they all look in reasonable condition.
With the car rolling, the brake pedal does absolutely nothing, I can only stop with the handbrake.

My only thought is that there is a massive air bubble in the system. Would I be right in assuming that the air would work its way to the highest point in the system i.e. master cylinder area?

I may be able to get my hands on a vaccuum pump, so I might give it a go with that if all else fails.

ziyaan · Post by **ziyaan** » Wed Jan 02, 2013 10:29 pm

how did you put the brake lines back in?

2 washers per brake line.... i made that mistake first.