rear bks locking up
helping a friend on this and i'm going nuts to figure it out.. disc/drum with pb's. each end has residual valves of different color. can't recall what was where.. anyways the issue is crappy peddle, bleads fine. after a while of driving one or 2 rear bks lock up. never have dealt with residual's before so did some googling. it appears the drum rears need a 10# valve. when i removed it and stuck in mouth i could blow threw ea end.. so no back pressure and most likely valve is bad... but why are the rears locking up is my problem... early this yr we replaced all the rear stuff. oh and he has an adjustable prop valve in rear too.
it's on a '34 chebby st rod.