What Brake System Do I Have? '89

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Fine Burban, Oct 26, 2013.

  1. Fine Burban

    Fine Burban Member

    Looking on the Autozone site for calipers since the two bleeder screws are pretty rusted / fused into the caliper I am given a JB7, JD7 or a JB5, JD5 system. Any idea on how I can find out which system I have? Thanks
     
  2. BurbanMan

    BurbanMan Member 1 Year 500 Posts

    I don't remember how to tell, but You went to the wrong parts house for brake parts. Unless you want to change them again in 6mo. Get them from napa. You'll pay a little more, but they last.
     
  3. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    In GM vehicles, those 3 digit alphanumeric codes are called RPO (Regular Production Option) codes. There should be a list glued to the inside of the glovebox with the RPO codes for the options that were factory installed in your vehicle.
     
  4. Manta22

    Manta22 New Member

    Is there a source to get copies? The one in my '94 Suburban is faded beyond reading.
     
  5. Fine Burban

    Fine Burban Member

    Like Shorty asked, is there any other way to get a copy OR can you figure it via VIN? Thanks for that info though.
     
  6. Crawdaddy

    Crawdaddy ↑↑↑ Has no life Staff Member 5+ Years 1000 Posts Platinum Contributor

    In short, the RPO codes for brakes correspond to whether the brake system is vacuum-boosted or hydroboosted, and what the GVWR of the vehicle is. So, if you can't read your RPO sticker anymore, but the sticker in your doorjamb that has all the weight ratings is, you can figure it out from there. Here's the list of brake systems with a vacuum booster:

    JB5 BRAKE POWER, DISC/DRUM, 6,400 LBS
    JB6 BRAKE POWER, DISC/DRUM, 7,200 LBS
    JB7 BRAKE POWER, DISC/DRUM, 8,400 LBS
    JB8 BRAKE POWER, DISC/DRUM, 10,000 LBS

    Similarly, here's the list of brake systems that used the hydroboost:

    JD5 BRAKE DUAL POWER, DISC/DRUM, 6,400 LBS
    JD6 BRAKE HYD POWER, DISC/DRUM, 7,200 LBS
    JD7 BRAKE HYD POWER, DISC/DRUM, 8,400 LBS

    Keep in mind that the weight ratings in the RPO codes reflect the GVWR and not the GAWR, GCWR, or any other rating. I hope this helps.
     
  7. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    I believe that GM, either through dealerships or through some other customer service source can look up the original RPO codes if you give them your VIN #. The one thing I would worry about is how far back they maintain those records -- 10 model years? 20 model years? I don't know.
     
  8. Conlan Rose

    Conlan Rose Rockstar 3 Years 1000 Posts

    They keep it for about 10-15 model years depending on vehicle type. For the trucks its only 10 because of the large volume that are built. I learned this talking to a GM rep who tried to find information on my truck but said that its too old to retrieve info on.
     

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