84CUCV
3/4 ton status
it a 91 chevy 3/4 ton 4x4 suburban. have a new MC, front calipers and all i did in the back was cut the drums. motor off i hear a hissing from the booster when i hit the peddle. could this mean the booster is shot? thanks
CK5
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pedal goes to the floor
- Thread starter 84CUCV
- Start date
GMC1977
1/2 ton status
It measns there is a gigantic leak from somewhere close to the booster. Check the firewall on the inside of the cab for brake fluid. if not make sure the brake lines are tightened where they come out of the booster
Randy92782
1 ton status
Look for any kind od leaks from where the master cylinder meets the booster. Also check to make sure there is no air in the lines or when you changed brakes the bleeder screw isn't loose
as stated look for any signs of brake fluid and check all your vacuum lines. hose clamp the big ones. also, did you bleed the back brakes too? remember bleed pass. rear, driver rear, pass front, driver front
If the pedal isnt' super hard, your booster should be fine. They don't go out that often. If it goes to teh floor, you have a master problem, or air in the lines somewhere.
84CUCV
3/4 ton status
bleed them 3 times. everything is tight. no leaks. the mater is rebuilt, so maybe they did it wrong. no leaks at the booster that i could find. still right to the floor
think i might get another MC. anyway to test the booster thanks
think i might get another MC. anyway to test the booster thanks
Note that when the booster fails, it doesn't provide any assist (i.e. no boost), so the pedal gets really hard, NOT soft. You have air in the lines or a leak in the hydraulics
Check softlines, wheel cylinders, calipers, the master, and consider vacuum or pressure bleed if you've not already.That said, testing the booster is easy; the test is whether the thing holds vacuum. Run the motor, and without using the brake pedal, turn the engine off.
Wait 15 minutes, and then press the brake pedal. You should get two or three normal presses and then it'll get really hard again.
I donno what'll happen in your case, but I suspect it'll be soft throughout, so the test is meaningless.
(I can't believe I just said "really hard" twice in public
)-- A
84CUCV
3/4 ton status
thanks
resurrected_jimmy
1/2 ton status
If you did not adjust the shoes outon the rear drums after having them turned it will cause a lot of pedal travel as well
84CUCV
3/4 ton status
i did adjust them out. will be back down there soon to work on it some more
GMC1977
1/2 ton status
no leaks in a line under the truck somewhere? my 67 wrecker had a big hole in the line about half way under the truck. leaked brake fluid like a waterfall tho
84CUCV
3/4 ton status
got back down there. bleed them again. no air at all. i ran it. got pushes on the peddle before it got hard. so that good. how do i test the vacuum or pressure bleed? thanks
84CUCV
3/4 ton status
to think of it. no i didnt. i got it put it one. and filled it up.
give an update when you get that done.
