87 two wheel drive 3/4 ton (tow unit)
brakes suck! I hit the brakes in a panic stop and it doesn't.
seem ok if i don't hit them hard. so i changed the rubber lines that go to the calipers, didn't help.
The pedal seems hard as a rock in the panic stop mode, can't get the truck to lock up in a panic stop.
am leaning toward the booster
I hear a hiss only when i hit the pedal hard
My experiences have been hissing all the time the pedal is down
but this hisses only when i first hit the pedal and then it stops hissing. I do know that it isn't good, especially pulling a trailer.
any suggestions?

Originally posted by fabricator
87 two wheel drive 3/4 ton (tow unit)
brakes suck! I hit the brakes in a panic stop and it doesn't.
seem ok if i don't hit them hard. so i changed the rubber lines that go to the calipers, didn't help.
The pedal seems hard as a rock in the panic stop mode, can't get the truck to lock up in a panic stop.
am leaning toward the booster
I hear a hiss only when i hit the pedal hard
My experiences have been hissing all the time the pedal is down
but this hisses only when i first hit the pedal and then it stops hissing. I do know that it isn't good, especially pulling a trailer.
any suggestions?

Sounds like a booster needs replacing......also check the line that goes to the intake and check for a "dry rotted" line.

Yeah, sounds like lack of vacuum. When my brakes go, the pedal hits the metal with little resistance. My 85 1/2 ton hisses but only letting the pedal out. She also locks up 35x15x15 tires with the stock brakes. Not even stock, its that shit raybestos brakes from pepboys.

charlo

vacuum seems to be working real well
will check the line anyway
but i am guessing i will be going to the booster store
line would be to easy
appreciate the replys

replaced the booster
brakes work like they should
it stops now
appreciate the replys