08 hino brake booster

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by o1reb, Aug 25, 2022.

  1. o1reb

    o1reb Bobtail Member

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    Apr 28, 2012
    bedford
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    08 ,238 hino brake booster motor runs constantly with key on question why is the steering gear plumbed in to the booster PN 0204022939 bad brakes hard steering king pins free
     
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  3. brian991219

    brian991219 Road Train Member

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    Because they use the power steering pump to create the brake boost under normal conditions. Other than the short self check during startup, the only time you should hear the booster motor running is when the engine is off or you have lost power steering pump pressure and you are attempting a brake application.

    Since you are having brake and steering issues check your power steering pump for failure.
     
    o1reb Thanks this.
  4. SmallPackage

    SmallPackage Road Train Member

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    Look up brake hydro boost to learn more about the concept.
    Common setup in automotive diesel powered vehicles that have “juice” hydraulic brakes.
     
  5. AModelCat

    AModelCat Road Train Member

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    Pretty much every diesel pickup, as well as any medium duty with juice brakes will use the power steering pump to provide brake boost. Diesel engines make no vacuum.
     
  6. o1reb

    o1reb Bobtail Member

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    Apr 28, 2012
    bedford
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    thanks we only work on class 8 feel like a rube asking but when you dont know ask someone
     
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