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brake booster 2wd vs. 4wd

Discussion in 'The Garage' started by Cornfield creations, Nov 7, 2005.

  1. Cornfield creations

    Cornfield creations 1/2 ton status

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    Just trying to figure out something, would there be much difference between a 2wd booster and a 4wd booster? Had good pedal before the cab swap, but since the swap the pedal has been hard. I don't see why they would be too different. I am gonna check the check valve and engine vacuum first. Then look into swapping the booster's.
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Hard pedal is a bad booster.
     
  3. Cornfield creations

    Cornfield creations 1/2 ton status

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    Well it's hard but not to the point I have to stand on it with both feet and pray it stops in time. Just a little harder than usual, which got me thinking that maybe the 2wd booster on the now 4wd frame and drivetrain isn't producing enough vacuum. Its alright, but I am pulling parts off this truck so we can throw it away. Anyone need a 79 2wd frame with a new 250 inline, and low mileage trans and rearend?
     
  4. 13lazer

    13lazer 1/2 ton status

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    i might want the motor and trans

    are you selling a l6 250? i am thinking about dumping the stroker in my blazer, and building it like original. 250 cu inch/ 3 speed saginaw. let me know? im trying to find one near the west coast. aaron@13lazer.com
     
  5. Cornfield creations

    Cornfield creations 1/2 ton status

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    Yeah that would be a long drive from Indiana to cali.
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    not much difference..

    Your booster probably has a bad diaphram in it,and its letting vacuum leak..My booster went south on my 79 C10,and I put one from a 73 K10 I had junked on it--bolted right up ,and the brakes work fine again...the hollander books at the junkyards list a bunch of different numbers depending on drum sizes,and say only certain years fit(delco VS bendix master cyl is different too supposedly,the bolt pattern is different)..

    I guess I got lucky,but if the trucks are the same (both 1/2 ton) ,have the same size brakes in the rear,and the boosters look identical,there is no internal difference I know of..should swap on ok..later ones after 1980 wont work on older 70's cabs...lots of things changed.. :crazy:
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    To test a booster, start the truck, let it idle for a few seconds, then turn it off, all without touching the pedal.

    GM says wait 45 minutes to test, but I think that's too long. Anyways, after letting it sit for awhile, you should get at least two full pedal assists without starting the vehicle. If you don't, it means the diaphram is leaking and the booster is bad.
     

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