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Hydroboost installed!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mouse, Jul 11, 2005.

  1. mouse

    mouse 1/2 ton status

    Nov 10, 2003
    Likes Received:
    Great Falls Mt
    While at the scrap yard looking for a second battery tray I found a complete hydroboost system for a 1/2 ton truck, in a '81 GMC. I bought the tray and everything for the hydroboost: pedal, brake switch bracket, boost unit, master cylinder, pump and all the lines ($120).

    Before it went in I cleaned up and painted the boost unit, and bought new pressure lines, pump (stock application - not all beat to #!@$ like my old one), and master cylinder (for the donor truck application).

    The tricky part: donor truck used "o-ring" style lines, my blazer uses regular flare line ends. To convert the pump, I used the valve assembly off of the donor truck pump. It threaded in right where my old one came out. So now the donor truck pressure line from the pump to the boost unit would work. I used a "T" to connect the gear box return line to the boost return line going to the reservoir. Finally, I used the adapters made by Lee Manufacturing - see bottom of this thread - (http://coloradok5.com/forums/showthread.php?t=130488&highlight=hydroboost) to adapt the boost unit fitting for the line going from the unit to the gear box, and used a new line listed for a 1978 1 ton diesel w/hydroboost (has flared ends).

    After bleeding the brakes and power steering systems I proceeded to pressure test everything - not a single leak. Although, the power steering pump took about 1 qt to fill.

    I also run rear discs - TSM large GM calipers and sky manufacturing brackets.

    I am very impressed with the performance and improvement. The brake pedal is a bit higher (mine was a tad lower than normal before), and has a firm feel. Brake application is easy and predictable, yet very powerful. It takes very minimal effort to lock the brakes at any speed. My rear brakes lock up a little earlier than the front. I may install a manual porportioning valve before winter.

    Bottom line - I highly recommend the conversion. I have never had this strong of brakes in the blazer before!
  2. tacoma

    tacoma 1/2 ton status

    Jan 14, 2005
    Likes Received:
    tooele UT
    That's good to hear. I intend to do a very similar swap. After tooling around in a big van w/Hydroboost, I am sold. It's schweeeeeet

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