NBS Master Cylinder Upgrade

Discussion in 'Engine Performance + Maintenance' started by KingKon, Sep 17, 2020.

Car Parts
  1. Reega

    Reega Newbie

    Messages:
    26
    Likes Received:
    16
    Joined:
    Jan 23, 2016
    Location:
    Knoxville
    I totally agree-firm pedal, but not braking force I needed-I went back to the old MC
     
  2. L31MaxExpress

    L31MaxExpress I'm Awesome

    Messages:
    1,356
    Likes Received:
    691
    Joined:
    Apr 21, 2018
    Location:
    DFW, TX
    I have a NBS van (03+) master cylinder in my van now, but it is paired with the larger NBS van hydroboost. Pedal is firm and I had more stopping power than ever. Wonder if one could use a NBS vacuum booster in a GMT400 and get back the pressure lost from the larger piston. Although a GMT400 hydroboost and pedal swap would work too. Hydroboost is an instant massive increase in braking pressure.
     
  3. east302

    east302 I'm Awesome

    Messages:
    2,260
    Likes Received:
    1,133
    Joined:
    Oct 4, 2013
    Location:
    Jackson, MS
    Same experience here. Felt like there was too little “bite” in the brakes.

    I wanted to like it.
     
  4. L31MaxExpress

    L31MaxExpress I'm Awesome

    Messages:
    1,356
    Likes Received:
    691
    Joined:
    Apr 21, 2018
    Location:
    DFW, TX
    Exactly, not enough WHOOAA when you really needed it. I swapped mine back out after noticing how much longer the stopping distances were after having to stand on the pedal with both feet to keep from rear-ending an idiot that shot over in front of me on the highway into the fast lane doing about 40 mph while I was rolling 75 mph. I was 300 lbs at the time too.
     
    HotWheelsBurban and east302 like this.
  5. east302

    east302 I'm Awesome

    Messages:
    2,260
    Likes Received:
    1,133
    Joined:
    Oct 4, 2013
    Location:
    Jackson, MS
    Yep, that sounds about right.

    It was almost like having a bad brake booster but not quite. The best I could describe it, it was like having smooth glass for brake pads. No grip, perhaps. It just wasn’t quite right and I wasn’t confident that it could handle an emergency braking situation.

    I’m sure there’s some hydraulics to it and think that @Schurkey (hope I spelled his name right) delved into it a while back.
     
    HotWheelsBurban likes this.
  6. kennythewelder

    kennythewelder B31-3 (6-G) certified

    Messages:
    4,017
    Likes Received:
    2,463
    Joined:
    Jul 14, 2014
    Location:
    Louisiana
    I saw this MC cover on a saleen mustang today at the car show. Think I will make one for my truck. 20200919_091610.jpg
     
    thegawd and HotWheelsBurban like this.
  7. Schurkey

    Schurkey I'm Awesome

    Messages:
    2,165
    Likes Received:
    1,354
    Joined:
    Jan 14, 2018
    Location:
    The Seasonally Frozen Wastelands
    1. Why are you posting about brake issues in the "Engine Performance" section???

    2. You've probably got JB5 brakes currently. A look at the glove-box sticker would confirm. The "5" brakes, like the JB3 brakes, use low-drag calipers which need Quick-Takeup master cylinders for proper brake action. It's not an upgrade to install a non-quick-takeup master when you need the high volume of fluid to move the caliper pistons at the beginning of braking.

    BUY THE CORRECT MASTER CYLINDER FOR YOUR VEHICLE, not some internet-rumor "upgrade" that has been "engineered" by people who DON'T UNDERSTAND HOW THE SYSTEM IS SUPPOSED TO WORK.
     
  8. thegawd

    thegawd I'm Awesome

    Messages:
    127
    Likes Received:
    216
    Joined:
    Feb 29, 2020
    Location:
    Southern Ontario, Canada
    I almost did the master cylinder upgrade a month or so ago. I have the adapter and a Tahoe to steal it from. I was replacing the vacume booster after it failed so I had a good opportunity. This is something I have wanted to do for a long time.

    I really wanted some damn good advice as to why not to do it. I was researching the rpo codes for my burb, i realized that my brakes were one of the best available on the 1500's and i just didnt think i had the engineering understanding to actually mess with it properly. Remember, gm put these trucks in a wind tunnel and actually made them aerodynamic.... that front valance ect.... they had the best engineers build these trucks, I just couldn't believe they would put shitty brakes on them and something else must be happening.... 20 year old system that needs to be rebuilt properly was my thinking. I didnt think I had a problem whatsoever with my master cylinder and couldn't bring myself to mess with it. My brakes worked absolutely fine before the vacume booster blew. I wanted some understanding as to why some people swear by the upgrade and some people change it back to the original. Well I reached out to Shurkey and his explanation lined right up with my thinking soooooo I didnt swap it.

    I still have the adapter in the glove box.

    Al
     
    HotWheelsBurban and SUBURBAN5 like this.
  9. SUBURBAN5

    SUBURBAN5 I'm Awesome

    Messages:
    1,394
    Likes Received:
    1,980
    Joined:
    Jul 18, 2020
    Location:
    Houston
    What if its JB6? What does that mean?
     
    HotWheelsBurban likes this.
  10. thegawd

    thegawd I'm Awesome

    Messages:
    127
    Likes Received:
    216
    Joined:
    Feb 29, 2020
    Location:
    Southern Ontario, Canada
    From here.....
    https://www.gmt400.com/threads/jb5-jb6-jb7-jb8-size-thread.39647/

     

Share This Page