Hi, after pedal hit the floor, made it home safely.
just replaced master cylinder & fluid and pads all around. Bled found this torn hydraulic vent line? Perhaps??
Test drove & brakes as before... to the floor. No fluid loss.

This line important?

 

2002 E 350. This located above rear axle at a hydraulic "T" w/ lines leading to each rear brake.

 

 

This broken line leads nowhere!?

 

The line going up is the axle vent and has nothing to do with the brakes.

 

excellent! Thank you. Thought it was a vent line.
Next guess is the HCU or booster since new master cylinder didn't do anything.
280,000 miles on it.

 

If there are no leaks, what color is your brake fluid?

Last year, on a different make van I lost my brakes and pedal would go to the floor, I could stop by pumping the brakes.

I had a mechanic look things over and found my brake fluid was black. Brake fluid should never be black from what I've heard.

Flushed the old brake fluid and the brakes were as good as new.

 

I would definitely re-bleed the M/C and the entire brake system. Usually when the booster goes bad the brakes become rock hard but still operate. With the pedal going to the floor and no fluid loss anywhere, I would think air still in the system.

 

Agreed. Bleeding the master can be difficult. Did you bench bleed it before installation?

Speed bleeders really help. They are basically a one-way valve that replace your bleeder screws. Open them up, and pump away. No air comes back in, so you can bleed all 4 cylinders with one person, much more quickly than using the old, "pump, hold pedal down, close bleeder, release pedal, open bleeder, repeat" method.

It's not a bad idea to put some tubing over the end running down to a container, but that's just for neatness. It will capture whatever comes out, instead of it spraying around. But it is not strictly necessary for the actual bleeding process.

 

My buddy, Jim, used one to bleed the front brakes on my '85 E150 yesterday after replacing the calipers and discs, his has a pressure gauge and a screw on container on it. Works like a charm.