[1999c1500]

Yeah,

It was the brake booster. I got a rebuilt one from auto zone -it was about $130 after I turned my old core back in.

It was a pain to replace on 2 counts.

1) I did have to break the seal on the mastercylinder and take the metal brake hose loose because there just wasn't enough room to get the booster out if I didn't. I got lucky and didn't have to bleed the brakes - I guess any bubbles just bubbled upward into the MC.

2) It was also hard to wiggle in underneath and disconnect it from the interior; I forget exactly what I did, but it worked fine with hand tools. You just don't have much room for your hands and arms and my hands are relatively small.

I was patient - it took maybe 2 hours for something that looks - at first glance - like an easy 20 minute on and off. The extra time was from taking my time and wiggling in and out.

Look,
Charlie

PS Once you hear that hiss , and feel that wooden brake feel it pretty much means the booster.

you actually don't have to break the seal of the master cylinder. I couldn't tell you what the part is called that the hard lines run to from the master cylinder that is located directly in front of the master cylinder, but it is mounted to a plate with 4 bolts that are very easy to get to and if you take those 4 bolts off you can easily slide the master cylinder forward enough to remove the booster without kinking any of the brake lines. I was just about to break the seal on my master cylinder when I realized this...hope this helps anyone that might need the help...

 

[1999c1500]

No, thank you. Your thread made it very easy to diagnosis the problem on my suburban. I assumed it was the booster when I heard the hissing while holding down the break pedal but its always nice to be certain when spending $120 on a part and a couple hours of work. Figuring out to take those 4 bolts off and slide the anti-lock mechanism forward was just my laziness not wanting to bleed brakes