1981 CJ7 Brake issue
I have an 81 CJ7 with an unusual brake issue. Upon stopping the front calipers are not releasing. Vehicle history: new front pads, rotors, calipers, new power bosoter, master cylinder and all new rear componets. I have bled and rebled the system to no avail. If the Jeep sits for a while the brakes will release and becomes moveable again until brakes are applied again. Any idea on what could be the issue?
even though you said you replaced the vacuum unit, it could possibly be bad. Did the old one do the same thing? Or perhaps the pedal doesn't came all the way back up. Or I'd even check the rod. Honestly sounds like some sort of vacuum issue though.
Replace the rubber lines that attach to the calipers.