So I just completed a manual transmission to auto swap, as well as longer brake lines, and long arm kit on the Jeep.. It sat for a long time prior to restarting almost 3months, but finally got it running. The brakes I can't seem to figure out why they are not working properly. I can pump them up when not running and they hold pressure fine, until I start the Jeep then the pedal has very little resistance and can be pushed pretty much to the floor before working at all. The brakes worked fine before the swap so not sure what could have gone wrong. I've re bled the system several times going through 1 1/2 big bottles of fluid, the pads are all newer. I have a wheeling trip this Saturday and really need to nip this in the but before throwing the family in the jeep.

 

Is the vac line hooked to the booster?

Also did you swap pedal assemblies? Make sure that's all lined up if you did.

 

Left the same pedals in, and I checked the hose as well as the one way valve attached to it. Also checked vacuum on the motor side.