Logic why this works with one person.
Typically, you bleed the brakes with one person in the car and another outside manning the bleeder valve. Apply pressure to the brakes, crack open the bleeder until the fluid stops flowing, close the bleeder, repeat the procedure. You close the bleeder up each time to keep air from getting back into the system.
I don't know about you, but I don't always have a buddy around to do this.
So, by putting the end of the tubing in the jar of fluid or using the quick bleeder I showed above(which has an internal tube that connects with the one on the outside and submerses the end in the fluid), air can't get back into the caliper. When you release the pedal, if it does have a suction, it will only pull fluid back up the line. No air.
Also, remember there is a compensation valve internal to the brake master cylinder (M/C). As you apply the brakes, it blocks the port to the reservior and routes all the fluid in the M/C to the brake lines. Inverse, letting the pedal up, the M/C compensation valve will unplug the port to the reservior. This inturn allows the M/C to draw fluid from the reservior and not the line. Thus, there will be minimal fluid drawn out of the jar/bleeder you use.
The same process can be applied to the clutch pedal slave cylinder (S/C) for bleeding air.
Last edited by Morphius; 02-01-2004 at 11:44 PM.