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Hydro Brake and Steer Problem - need help bad

Discussion in 'The Garage' started by crawlink5, Jan 29, 2006.

  1. crawlink5

    crawlink5 1/2 ton status

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    Problem solved - lines were backwards

    I need to drive this Blazer to work tomorrow.

    I just installed a Cummins 4bt in my 78 Blazer. Put in Hyd boost brakes. Now I can't steer while pressing on the brakes. Also, if I saw the steering wheel back and forth while pumping the brakes, the pedal will drop to the floor sometimes. Steers great if I'm not pushing the brake pedal.

    I know I need to bleed my brakes more, but I didn't think that would affect the steering.

    What should I check? Does the hyd lines need purging somehow? Pump is gear driven, so no belt. Pump came on motor.
     
    Last edited: Jan 29, 2006
  2. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    There probally isn't enough pressure being put out by your pump to provide adequate pressure to both.

    I dunno if you are running a saginaw pump or not (don't know the first thing about Cummins engines) but they have a little pressure regulator on the back that the output hose screws into, and you can modify that regulator to boost the pressure / flow so it can handle both systems at once.

    However, being a diesel, I'd almost have expected that it'd have the pressure for both systems already, as the truck it came from likely had both systems...
     
  3. crawlink5

    crawlink5 1/2 ton status

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    Same pump as Chevy I would think except for gear driven. It is for Hydroboost system as it has the three lines coming off it. Engine is an 86 from a Frito-Lay truck.

    Hydroboost and master are new for a 85 Blazer with a diesel. Steering box is 1978 Blazer.

    Rear is 78 Caddy Eldorado calipers. Front is d60 calipers.

    Could it be that the brake pedal is going too far down sucking up too much fluid pressure? I'm about to start bleeding again by taking off the master, bench bleeding and then bleed at the proportioning valve, etc all the way out.
     

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