Who Has HYDROBOOST on there '90 or '91 K5

Discussion in 'The Garage' started by 90blzr, Aug 14, 2004.

  1. 90blzr

    90blzr 1/2 ton status

    Mar 25, 2001
    Likes Received:
    SO CAL
    Who Has HYDROBOOST on there \'90 or \'91 K5

    Wondering what year you got your master cylinder, steering pump and hydrobooster from. Not sure if the ABS had anything to do with the set up or not.

    Is the pump different from the older years, or just the pulley? (newer 89-91 had the serpentine pulley)

    Basically want to know if I can use any year hydro system on my '90 K5...or if it has to be one from a 90 or 91 due to the ABS and serpentine pump.

    Also, is the hydro steering box any different from a non hydro box?

    One more thing....some say you have to replace the pedal assembly, others dont...whats the deal with that?
    Pretty much a bolt in deal?
    any tips? /forums/images/graemlins/ears.gif /forums/images/graemlins/thumb.gif
  2. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

    Apr 20, 2004
    Likes Received:
    Northern Colorado
    Re: Who Has HYDROBOOST on there \'90 or \'91 K5

    I don't exactly fit your scenario but I think I can help some. I have an '84 that originally had a 6.2 with the hydroboost. When I switched to the 350 I kept the hydroboost. Here's what I've found out over various upgrades.

    First off in order to get the p/s pump from the 6.2 to fit the brackets on the 350, I had to weld them up custom like.

    Since then I've swapped in a serpentine belt setup. It was the kit from GM Perf. Parts that included all brackets and the accessories. The p/s pump included worked fine. The hoses attached just fine. The only thing I had to do was tee together the return lines from the gear box and mc. This is because on the original p/s pump there is an extra fitting on the reservoir for the second return line.

    I did some research about whether or not the p/s pump in the kit would work for the hydroboost. Through checking part numbers at parts stores the only difference I could find is the reservoirs. The pump themselves had the same part numbers. What sold the deal for me was when I found a company that specialized in upgrading cars, primarily they focused on corvettes, and they used the standard p/s pump with the return lines teed together.

    I've had this setup on the truck for several trail runs now, and never a problem. I've been on a steep downhill incline braking hard holding the truck at a stop, and had no problems turning the 33s with the truck at a stand still idling.

    The only change I want to make is to add a p/s cooler.

    FYI: when crossing over the part numbers for the accessories in that serpentine belt setup, they seemed to match up to early 90s vehicles.
  3. u2slow

    u2slow 1/2 ton status

    May 9, 2001
    Likes Received:
    BC Canada
    Re: Who Has HYDROBOOST on there \'90 or \'91 K5

    My '91 crewcab had the multi-groove belt on p/s pump. Its not a true serpentine, its just the old v-groove stuff with a different pulley. You can swap the pulleys with the right tool.

    I know you could remove the ABS without ill-effects. /forums/images/graemlins/grin.gif I can't speak for its behaviour with hydroboost - if it even makes a difference at all.

    Nothing changes with the steering box. Just make sure your pump, hydroboost, steering box, & hoses are the right type - all imperial or all metric... changed about '81(?) or so.

Share This Page