Does anyone know the "nominal" system pressure of a typical brake system under "normal" braking?? I searched here and also on Google, but didn´t find anything conclusive.

There´s a retard here on one of the Brasilian 4x4 lists that is looking to go cheap on his brake lines. I keep calling him an idiot, saying that saving a few bucks will end up getting him or someone else killed. He had himself convinced that he can use fawking common rubber hose with barb fittings and hose clamps......:rolleyes: Thankfully, he´s now at least conceded that something more robust is necessary.........

Obviously, the system pressure is directly proportional to the pedal pressure, so a panic stop would generate 2 to 3 times the normal pressure. But, for the sake of this discussion, does anyone have an idea of a ballpark number for the pressure created during a typical brake cycle??

TIA

Originally posted by billj
Does anyone know the "nominal" system pressure of a typical brake system under "normal" braking?? I searched here and also on Google, but didn´t find anything conclusive.

There´s a retard here on one of the Brasilian 4x4 lists that is looking to go cheap on his brake lines. I keep calling him an idiot, saying that saving a few bucks will end up getting him or someone else killed. He had himself convinced that he can use fawking common rubber hose with barb fittings and hose clamps......:rolleyes: Thankfully, he´s now at least conceded that something more robust is necessary.........

Obviously, the system pressure is directly proportional to the pedal pressure, so a panic stop would generate 2 to 3 times the normal pressure. But, for the sake of this discussion, does anyone have an idea of a ballpark number for the pressure created during a typical brake cycle??

TIA

I don't know what typical is, but I have used a line pressure gauge and measured it as high as 1500 psi in a stock boostered TJ. I run hydroboost in mine and maxed out the 1500 psi gauge with it.

Vanco claims pressures as high as 2600 or so with their HB system. Can't verify that though.

As far as your panic stop. I don't think that raises the pressure. Full pedal is full pedal and the system can only generate so much and then it's done.

You didn't search very well. I used GOOGLE and got these on the 1st page.

Brake pressure estimation guide by SAE (http://www.delphi.com/pdf/techpapers/2001-01-0595.pdf)

brake pressure gauge (http://www.corsa-inst.com/sensors/pdfs/ps2200g-b.pdf)

Mac brake tool kit (http://www.mactools.com/content/cool_tools/press/pdf/20020522_mac_pr.pdf)

Originally posted by JeepinIan
You didn't search very well. I used GOOGLE and got these on the 1st page.

Brake pressure estimation guide by SAE (http://www.delphi.com/pdf/techpapers/2001-01-0595.pdf)

brake pressure gauge (http://www.corsa-inst.com/sensors/pdfs/ps2200g-b.pdf)

Mac brake tool kit (http://www.mactools.com/content/cool_tools/press/pdf/20020522_mac_pr.pdf)


I saw those pages, but they give no conclusive info, just mention the max range of the gauges.

Using your logic, I outta be able to go 160 km/hr in my Zuk. After all, the speedo goes that high.......:rolleyes: :flipoff2: :D

Originally posted by mrblaine


As far as your panic stop. I don't think that raises the pressure. Full pedal is full pedal and the system can only generate so much and then it's done.


Thanks for the info.


Now concerning the above statement, my training in hydraulics would lead me to believe that the system pressure is directly proportional to the force being applied to the M/C thru the pedal. The amount of pedal movement influences the effective volume of the fluid in the system, thus indirectly affecting system pressure.

You are correct as you say "full pedal is full pedal" as long as there is a mechanical stop on either the pedal or M/C. With no such limiting factor, increased pedal pressure will result in increased system pressure.

In any event, in regards to a panic stop, the pressure spike to the system would be very different from a normal braking situation.........



;)

Originally posted by billj



I saw those pages, but they give no conclusive info, just mention the max range of the gauges.

Using your logic, I outta be able to go 160 km/hr in my Zuk. After all, the speedo goes that high.......:rolleyes: :flipoff2: :D

But you asked this

Originally posted by billj

But, for the sake of this discussion, does anyone have an idea of a ballpark number for the pressure created during a typical brake cycle??


So, all you gotta figure is if a gauge is most accurate in the middle of it, then the "ballpark" number is around 1500 psi.

When doing some brake setup on my friends oval track race truck (http://www.wilsmith.com), we used a pressure gauge and were seeing pressures of 750-1200psi at the calipers from a NON-power Dodge master cylinder with someone just putting normal pressure on the brake pedal.

I know that plain rubber hose won't work, since I've seen it ballon and explode when an idiot friend tried to use it on the high pressure side of a power steering system. Stock power steering makes 1000-1200psi, and he wasn't even using the steering - he just started the engine and the hose ballooned up and popped! I had to yell at another idiot friend to get his face out of the way because he was just staring at it awe-struck as it was about to pop. :D

Can you use that as some real-world examples?

Later!
Richard

Originally posted by JeepinIan


So, all you gotta figure is if a gauge is most accurate in the middle of it, then the "ballpark" number is around 1500 psi.

OK, OK, I´ll concede this one to ya...........:p ;)