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Hydroboost/Power Steering issue

Discussion in 'Steering, Suspension and Wheels' started by knkreb, Apr 19, 2011.

  1. knkreb

    knkreb The Bus Driver is here!

    May 3, 2008
    In my gasser van the other day, I had to take it out for a quick ride to pickup two escaped dogs out the front door. Basset hounds can't find their way home once they leave for some reason, but I digress....

    So, in a hurry, I start up the van, head to the end of the driveway and have to put all my weight into the brake pedal to stop, and heavy-ho to turn the wheel. After a bit, the brakes came back up and the steering did to, but it did intermittently mess up still. Fluid level find in the power steering reservoir.... so now looking for which area to start looking in. The pump made a sound (not the bypass sound) every once in a while too.
  2. ak diesel driver

    ak diesel driver 6.5 driver

    Feb 7, 2009
    sounds like the pump might be on it's last legs
  3. btfarm

    btfarm 300,000 Worth Staff Member Moderator

    May 12, 2008
    Sandwich, Illinois
    Does the pedal pump up? Could be the seals in the master cyl are worn out. They tend to work a bit better when warmed up from use but pretty bad when cold is a first indication.
    But yeah it sounds like the pump is likely starting to go bad.
  4. WarWagon

    WarWagon Well it hits on 7 of 8...

    Nov 15, 2009
    Gasser van with hydroboost?

    I would check the belt and see if it stretched out and is starting to slip. Then remove the belt and tug on the PS pulley to see if the shaft is broken.

    Check for leaks in the cab and on the firewall by the hydroboost.

    Last, the Hydrobooster gets preference so if it mucks up the power steering can go away too.

    Sounds like the pump stopped rotating or was not generating pressure. Stuck relief valve?
  5. knkreb

    knkreb The Bus Driver is here!

    May 3, 2008
    Yepper, a gasser with a hydroboost... 1 ton Express 3500.

    Pulley was turning. No bypass sound either. I read something online in alldatadiy about a vacuum test on the reservoir in case there is air the has entered the lines. Apparently GM has put out a bulletin on a lot of "no-defect found" warranty returns.
  6. handcannon

    handcannon Well-Known Member

    Nov 21, 2009
    Albany, OR
    I have two Asto vans with the 4.3 vortec V6 and both have hydroboost.

    I know you are not having problems with fluid loss. But for those who are losing fluid, another place to check is between the master and boost unit. There is a weep hole under the booster at this joint. If the booster front seal starts leaking it will show up as a mess on the fender liner and frame below, in addition to the loss of fluid out of the reservoir.

  7. chevyCowboy

    chevyCowboy I might be crazy but i ain't dumb

    Nov 16, 2008
    Springfield Nebraska
    is that easy to fix? where can parts be bought for the hydroboost. mine is leaking quit abit i will have to look tommorow to see if it seems to be coming from that weep hole. i dont really want to have to replace the whole thing a seal shoudl be aot cheaper.
  8. handcannon

    handcannon Well-Known Member

    Nov 21, 2009
    Albany, OR
    I just replaced the whole hydroboost unit, didn't mess with trying to replace seals. Just unbolt the master and gently pull it away from the hydro unit. You don't need to do anything with the brake lines as long as you are careful. Then remove the lines from the hydro unit and unbolt the unit from the firewall. It's really easy to do.


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