1998 Suburban-2wd 1500-Hiss-poor braking-Power brake booster.

Discussion in 'Lifted & Offroad Suspension' started by phoebeisis, Mar 11, 2008.

  1. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    The brakes on my 1998 2wd 1500 Suburban have been bad for a while.I didn't really notice that they were "broken" until today.Initial pedal effort was very hard, but I got almost no brake effect until the pedal was pushed maybe 1"-then it would brake, not great, but I did have brakes.
    It finally crossed my mind that it was braking like a car with the engine off,and no power braking.
    I finally turned the radio off and listened-there is a loud hiss when I press on the pedal.I got under there,and pressed the pedal with my hand,and with the other hand I could feel air blasting out of the brake booster.I can feel spongy foam stuffed inside the booster around the brake rod-guessing this isn't a seal, but it just foam to hold some lube?
    1)Where can I buy a booster-OEM-most cheaply?Any online discount Chevy parts sellers.I bet autozone has a rebuilt one in stock, but I've had problems with autozone parts in the past.
    2)How hard a job is it.I have a Haynes repair manual-it mentions that I might have to remove the lower dash panel,and unbolt the steering column to get access to the pushrod and booster mounting nuts. I sure hope I don't have to do that?
    3)What trick is there to getting the lower dash panel off without breaking something?Those things usually have some sort of clips you can't see,and they always drive me crazy.
    4)Any tips on the easiest way to do this?
    Paying someone isn't an option.I'm broke(medical debt) in school( for teacher's certification),and substitute teaching($62/d),so it is strictly DIY.I'm not so flexible-57 yo-but I can get under the dash.
    Any tips appreciated.
    PS-This is the first thing to break in 10 months of ownership on a 198,500 mile vehicle-not bad for $2950.The PO had the trans rebuilt at 185,000,and the AC,and intake manifold gasket at 155,000-so it is worth repairing.
  2. type 787x

    type 787x New Member

    Just wondering if you found the fix? My '99 Sub 1500 4WD is having the exact same symptom that you describe. I suspect it's the booster but nothing looks wrong externally. I'm a mechanic but I hate to go fishing on this one, that booster looks like a pain to replace.
  3. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts


    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.


    PS Once you hear that hiss , and feel that wooden brake feel it pretty much means the booster.
  4. type 787x

    type 787x New Member

    Thanks for the quick reply!

    I'd already resigned myself to squeezing in under the dash to replace the booster, your answer gives me hope I won't be wasting my time and getting cramped up for nothing.

    Plus I was getting a little concerned about having to e-brake that big thing if necessary. Not exactly a lightweight.

    Appreciate it.
  5. type 787x

    type 787x New Member

    Job done, booster fixed it.

    Worst part was getting the small retainer clip off the brake pedal post. Complicated little clip and you can hardly see it much less get to it.

    Bought a new clip so I could see how to release it. Still a major pain but finally got it to pop off.

    Thanks again for the info
  6. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Glad it worked out ok. I remember that it was really tricky working under the dash near the firewall. I think I ended up using an old curved hemostat to hold "something" while popping something else in or out. I don't remember the details, but I remember feeling VERY LUCKY that I managed to get the firewall stuff apart and back together..

    I drove around for about a week with no booster. Needless to say, it didn't brake very well with no booster; I kept my speed waaaay down.

  7. charlieo

    charlieo New Member

    How to install a new brake booster on a 1996-2000 Suburban, Tahoe, or Truck

    Start here: http://www.youtube.com/watch?v=leW0weGJGjc

    However, he doesn't show you how to get the clip off, does he? There's a reason. It is nearly impossible. However, I was finally able to get it. Here is what I did:

    First of all, to get to the nuts under the dash, pull the foam padding off of the firewall to expose the nuts.

    As I said, the hardest part is getting the clip off of the rod that holds the brake light switch and the "plunger" that is attached to the booster (that goes through the firewall). The clip is on rod that is on the upper part of the brake pedal. The clip is on the passenger side of the rod. It holds the white plastic brake light switch on the rod. The only way to get the clip off is to destoy it. However, because of the angle, it is nearly impossible to get a screwdriver under it. I found the best tool to use is a Door Upholstery removal tool. It is somewhat like a screwdriver but is curved on the end with a "V" cutout on the "blade". Once I got it off, it was relatively easy to follow the instructions to remove the booster. However, getting the new clip on (available only at the dealer), was difficult. I used the upholstery tool again along with some double-stick tape to hold the clip on the tool. I then was able to access the rod that goes through the plunger and brake light switch and just pushed the clip on. It doesn't go on easy, but if you have it lined up just right, you just push hard and it will go on the rod and lock (permanently). I've attached a few photos to help. Good luck.

    Attached Files:

  8. 1999c1500

    1999c1500 New Member

    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...
  9. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Great tip-thanks!
    I just took a look at it-looks like it it the plate the antilock brake mechanism is bolted to
    You are right- 4 bolts-should move enough to allow not breaking the seal
    Guessing that is exactly why they bolt it to a removable plate instead of just to the wheel well.
  10. 1999c1500

    1999c1500 New Member

    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 :)

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