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HELP Regarding Brake Booster Swap

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by clubba68, Jul 20, 2004.

  1. clubba68

    clubba68 1/2 ton status

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    It failed to cross my mind until just now, but has anyone done the swap from NO brake booster (non-power drum brakes) to adding a brake booster? That is what is about to happen in my rig and I just was wondering if anyone had any advice or knows exactly what I am going to need/what modifications are going to need to be made. /forums/images/graemlins/1zhelp.gif
    Thanks!
     
  2. BobK

    BobK 1/2 ton status

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    Well I guess you'll nedd the brackets that go between the booster and the firewall.

    The proper length pushrod that connects the pedal to the booster linkage.

    Vacume hose to supply vacume to the booster.

    Prop. valve.

    not sure if the orig. M/C can be retained.Don't think so though.
     
  3. Yukon Jack

    Yukon Jack 1/2 ton status

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    I am putting a 1978 power brake booster from a 3/4 ton 4x4 onto my 69 K5. I had to cut a small portion of the bracket on the fender side of the booster (this eliminated one of the bolt holes for securing to the firewall). The rod going into the 78's power booster that attaches to the brake pedal was too short so I had to build a bracket that attaches the rod to the brake pedal securely.

    I will have to do a slight modification to the brake lines as I am adding disk brakes at this time. The new brake booster uses a porportioning valve that has one brake line going from it for the rear brakes and two lines from it for the front brakes. The Blazer was drum brakes all around so there were just two lines and down on the frame the front brake line was split to feed both front brakes.

    Hopefully it won't be a problem but I am only using 4 of the bolts to secure the brake booster to the fire wall. The 78's booster was secured to the 78's firewall with 6 bolts.
     
  4. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I would say go to the junkyard, find any '67-72 truck or first gen blazer that has a power brake booster, and grab the bracket and pushrod that goes from the firewall to the booster. /forums/images/graemlins/peace.gif
     
  5. clubba68

    clubba68 1/2 ton status

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    [ QUOTE ]

    not sure if the orig. M/C can be retained.Don't think so though.

    [/ QUOTE ]

    I have a MC from a Corvette (stock 4 wheel discs) that I am going to use.
     
  6. BobK

    BobK 1/2 ton status

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    I run one of those as well.Works well. /forums/images/graemlins/thumb.gif
     
  7. 71RestoRod

    71RestoRod 1/2 ton status

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    BobK,

    So you have the 3/4 ton booster and a Corvette M/C with 4 wheel disks? That sounds like a really trick setup. Ahhh now with the questions!!

    Can you tell me what year(s) and/or a part number for the Corvette M/C? Is it a direct bolt-up with the 3/4 ton booster? Does it provide more volume for the disks... is it a stiffer/softer peddle feel? What did you use for the prop valve? Do you use an adjustable pressure valve for the rear disks? Pictures!!??

    Many thanks in advance.
     
  8. BobK

    BobK 1/2 ton status

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    78 Corvette M/C and 3/4 ton booster.
    [​IMG]

    Not sure of the spec's such as bore size or travel length.
    It bolted to both my 1/2 ton and the new 3/4 ton Booster with NO mods.

    I used a 4 wheel disc prop valve from a 82 Eldorado.No need for an adjustable prop valve.It has pretty even brakeing.

    Pedal is firm with quick response.
    [​IMG]

    [​IMG]
     
  9. 71RestoRod

    71RestoRod 1/2 ton status

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    Very nice setup BobK... and an awsome K5! Thanks for all of your help.

    Resto
     

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