brake problem

i wa sdriving my 88 c/k coming up over the crest of a hill where traffic was stopped . i pushed on the brake to the point of locking up the front end but wasn't stopping in time so i pushed harder to the point where the brakes gave out. luckily i was able to steer into an empty lot an drive out the momentum. I have no braking now the pedal goes to the floor and pumping them gives a little resistance but they fade fast. I was thinking a master cylinder went. i still have fluid in the resevior. my friend says it might be a whell cylinder but if that was the case wouldn't i have some kind of brakes left?

A bad master cylinder can bypass internally. If there was a leak in either the front or rear the proportioning valve would set to block that leak and turn on the RED brake light and leave you with either front or rear braking. Best to check all 4 corners and all lines for leaks. In the event you get a new master cylinder be sure to do a "bench bleed" on it. They usually come with a kit and instructions on how to do this. From your post I would suspect the master. Best get it fixed ASAP.

first what happened to your emergency brakes. commonly called parking brake. you use them when your main brakes go out to stop the truck.

look under the truck. do you see any wet spots, wheel cylinders when they go out will drip down the tires. a brake in the line will leave wet spots on the frame and ground.

your master cylinder will leak on the back side of the unit or bypass internally.

my e brake still works but i didn't get too use it, i had one foot on the brake pedal and the other on the clutch, it happened so fast. it was wet that day and i didn't see any rainbows on the road, i have yet to see the insides of the tires. i didn't notice anything damp on the booster. I'll get under it to check.

my e brake still works but i didn't get too use it, i had one foot on the brake pedal and the other on the clutch, it happened so fast. it was wet that day and i didn't see any rainbows on the road, i have yet to see the insides of the tires. i didn't notice anything damp on the booster. I'll get under it to check.

since you have a vehicle this old you probably don't have much cash to put into this...

all the wheels need to be removed and a full brake inspection including all those brake lines/hoses...

then theres the rear drums which if old need be replaced...

go to a scrap yard to get parts for the brakes I have found new brake parts on these scrap vehicles..

all the wheel cylinders are dry so im guessing the master is internally bypassing. I'll be replacing the lines too they look to be at 20% lol.