Hi,
I have an '85 F150 2wd manual and I just installed a new master cylinder and brake booster. I bench bled the master and installed the components and pumped the brakes in an attempt to bleed them. i pumped the brakes for a long time and still i saw air escaping from the master cylinder reservoir. I did not bleed the calipers.

The brakes feel fine if the booster vacuum hose is not connected, when the hose is connected i have a light pedal with a whooshing sound when a press the brakes. This is the same result since before i replaced the old booster. I did a lot of research but haven't found anything definitive in my mind. Maybe there is a leak somewhere in the system or the new booster is bad? I did have a rough idle but that oddly corrected itself. The booster is a reman from rock auto, they didnt have any new units which is what I wanted...
I'd appreciate the help, thank you.

 

The proper way to replace the master cylinder without bleeding the whole system is to pull the lines and cap them off, change out everything with a bench bled master like you did, put the lines back on the master cylinder, and leave them loose. Get someone to push the pedal down and hold it, fluid will leak from the loose fittings, and then tighten them up and tell the person to lift the brake pedal. That usually works. If you did not have a helper, you just pushed a lot of that air in the line, and you will have to bleed the whole system, with a helper of course.