Breaks locked up

So yesterday On my way to town I could feel the brakes engaging on their on. So I pulled into sonic and tried to back out andAll four brakes were locked . I put it in 4x4 and it killed the engine . I tried forward and reverse and it wouldn’t budge so I shut it off. I broke the brake line loose at the booster and bled it off and cranked it up and drove home . Anyone ever have this happen? Is it a hose issue or booster issue? If it would have locked like that going down the road it would have been bad!

 

Hard to determine honestly. We can only assumed. Potentially the one way check valve on the booster, bad booster, abs pump acting up, MC not returning, closed/kinked or clogged line etc

 

My idiot's guess is the MC is leaking into the booster

if you dont find that early ......the MC wipes out the $500 booster


I replaced my original MC couple years back as a preventive move



brake fluid is so corrosive......could be used as paint stripper
its affinity for oxygen and moisture makes it highly reactive