yalls helping thoughts

[bigredchevy]

i have i 86 crew cab c20, vacum brake booster jb7 ect... ive changed every thing now twice over in two mounths first booster faild (pedle gate hard) and did shoes wheel celinders pads for front and lines in back wheight vale stoped working then so bypassed that now two mounths later i drive 30 miles to town ond stop for food now no brakes soft pedle to the floor slowly drive home and get a new booster and master cylinder onder warenty boom still the same thing nothing ive bleed it agin and agin, no air, no leks, no puddles, still no pedle when running im at my wits end, this is two weeks with no truck and thats all i have to drive plz help with idears

[donut]

E-brake work? The reason I ask is i once got the self adjusters backwards and brakes loosened themselves out of adjustment.

You should have hydraulic pressure, it's a sealed system. When you bleed are you getting anything? Was the new master bench bled? Is there any brake at all? Fronts and rears are separate, usually if one goes the other will still work (not well, but something)

I don't know the symptoms of a bad proportioning valve, but sounds like you have a BIG slug of air, or a big leak that you don't see yet.
Air is compressible, brake fluid isn't.

[76Charlie]

Has to be air in the lines or a serious misadjusted brake line

[motornut]

are the rear ebrake bars in?
and the rears ajusted up?
the rear ajusters in right and springs ?
loose greased and working? do you know?

[bigredchevy]

yea it was all working fine for two months and then gone to the floor soft pedle but no brakes.last night i pluged the booster off so no vacum and drove to the store with brakes just had to stand on them lol, i locked them up a few times trying to see if the proportining valve reset and they all locked up (tire marks from all four on road) idk any more

[rs72z]

The best way to rule out a bad mastercylinder is to get some plugs that fit the mc ports and plug them. Them step on the pedal, if it goes down the mc is bad if not your problem is else where.
I also second checking the shoes and make sure they are adjusted and nothing has broke or come loose.

[terryj]

I'm starting to wonder if the check valve on the V/booster is leaking.

[rs72z]

Originally Posted by terryj

I'm starting to wonder if the check valve on the V/booster is leaking.

The booster would only cause a hard pedal, imo.