Brake System Leak Check

[72barracuda]

My new brake system is nearly complete and I want to do a leak check with air while the system is totally dry before I go any further. I was thinking about modifying an old master cylinder cover and gasket to accept a barb so I can connect an air hose and set the pressure at 20 psi and see if it holds. If it looks like it leaks I can then find the leak by brushing on soapy water. Is there an easier way? Are there any problems with this? Do I need to only inject air in one reservoir or can I cut away the whole gasket interior and just leave the seal around the perimeter? I got the idea when I saw a youtube video of a guy flushing his brake system using a garden sprayer. Since I am using stainless steel lines I would like to find the leaks now vs later.

 

[moparleo]

Unlike checking a tire rim for a leak by dunking in a water tub, your system is a hydraulic system Brake fluid is needed to seal the brake system at all of the rubber sealed parts like the piston cups on your wheel cyclinders, also the piston seals in your brake calipers if you have front disc brakes. You want the brake system to be as air free as possible. Did you make your own flares with this system ? If they are factory made and you only installed them and did not cross any threads or over tighten, you should be good to go. Use high quality, high temp brake fluid from a virgin container. This assures no moisture in the fluid which is the number one worst thing to have. When braking the heat generated by the friction of the pads/shoes is transmitted to the brake fluid. As you know, water boils at 212 degrees at sea level. Brakefluid temps exceed this temperature every time you stop. When the water boils off in the system it turns to a gas which is compressable. This means spongy to no brake pedal on a high speed or long brake pedal use such as going down a hill.

Here is a little brake info for anyone following this thread. Leo

All conventional brake fluids used in cars and motor cycles are hygroscopic, that is, they absorb water from their surroundings. Strange though it may seem, the flexible hoses incorporated in braking systems are permeable to water and in time enough, water can find its way into the system via the hoses, and seriously affect the brake fluid's performance. This water reduces the boiling point of the fluid (ie, it lowers the temperature at which gas bubbles begin to form). When these bubbles form, they turn a virtually incompressible liquid into a mixture of gas and liquid which can be compressed quite considerably, thus severely reducing the efficiency of the brakes. In this situation, a driver finds that the brakes feel spongy. Brake-pedal travel will increase and it may be necessary to 'pump' the pedal to get the brakes to function effectively. However, when the brake fluid reaches a temperature at which the water in the fluid causes gas to be produced, which is equal to the volume swept by the piston in the rake master-cylinder, vapor-lock occurs and the brakes become inoperative. When this happens, the first indication the driver has that something is wrong is when he applies the brakes. The pedal goes down to the floor and the car carries on at undiminished - and possibly fatal speed.

http://www.bing.com/videos/search?q...&mid=259435535CCFB9E644BC259435535CCFB9E644BC

 

[Moparparts]

Use DOT 5 in the system it will not hurt the paint if you get or have any leaks