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Power steering problems continued

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 74Chev, Mar 23, 2003.

  1. 74Chev

    74Chev 1/2 ton status

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    After replacing the steering box, flushing the system, and putting in another new AGR pump the steering is still stiff. At idle you can't turn the wheel at all!!! If you hold it at about 2000 rpm it works really good. I used Valvoline steering fluid, it seems kind of thin and foams up pretty fast. I also noticed it gets hot real fast and I have a huge steering cooler. Is it possible that this fluid sucks and is not thick enough to build any pressure. I am turning 39" boggers. The belt is a 3 years old but looks fine and is tight, I can't hear it slipping??? I have been working on this problem for two weeks replacing parts flushing and still the same sh**. Any help would be greatly appreciated, this is realllllly trying my patience. /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif
     
  2. R72K5

    R72K5 Banned

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    hoses backwards ?
     
  3. bablazer73

    bablazer73 1/2 ton status

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    maybe a stupid question, but. are all the pully's the stock size?? I have seen people change pully's and mis match them. pully sizes are critical to keep pump speed correct. Just a thought that maybe pump was turning to slow. You might be able to find a smaller pully for the pump and speed it up (like when reving the engine) I know my steering on my 76 got harder when I put the 40's on it, but it loosened up alot when it tore the box out of the frame!!
     
  4. 74Chev

    74Chev 1/2 ton status

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    I did change from the keyed type pulley to the tapered type required with the AGR pump. I pulled it off a 2wd in the junk yard. I am pretty sure they are the same size but not positive. I have a smaller pulley off of a car pump. Would this help increase the speed of the pump quite a bit?
     
  5. 74Chev

    74Chev 1/2 ton status

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    quote]hoses backwards ?

    [/ QUOTE ]

    I think they only can go on one way. The fittings are different sizes.
     
  6. bablazer73

    bablazer73 1/2 ton status

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    A smaller pulley on the pump will increase pump speed. If you know the diameter of the pully's there is a way to calculate rpm's. but I don't know it.
     
  7. Bob Hope

    Bob Hope Registered Member

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    Maybe one of the hoses is plugged. it sounds like that is the only part of the system you haven't replaced.

    the high temperatures and the foaming fluid also indicate there might be a restriction in the one of the lines. I would try the hoses, they should be pretty cheap.
     
  8. the professor

    the professor 1/2 ton status

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    Since you replaced the pump;

    We need to look at someting else;

    How does a P/S gear operate..??

    This aplies to just about ALL PS units, be they worm & sector or rack & pinion

    The pump, when you are not turning the steering wheel...generates NO pressure...it circulates oil through the PS gear, and through a cooler if there is one, back to the pump

    Inside the steering gear, on a worm & sector type steering box (the kind you have), there is a "worm gear"...attached to the steering wheel, and a "sector shaft"..attached to the front suspension

    The "sector" is actualy just "part of a circle"

    There are modern improvements over the original design, and what you might find on a lawn mower..its 'recirculating balls" to reduce friction..I won't go into detail, as it would just confuse this

    Attached to the end of the worm with the balls, is a piston...(the worm is inside the piston")...this piston has a gear on the outside, that meshes with the "sector"

    This piston has a seal-ring on the outside, that lasts, almost, but not quite forever

    Oil circulates freely through both sides of the piston

    When you turn the steering wheel (this is for all steering designs, but early Honda's), a "spool-valve", "restricts" the oil flow from comming OUT of one side of the piston, and "restricts" the oil from going INTO the other side..

    This causes a differential pressure and you get "boost"

    Only as much pressure is developed by the pump, to overcome the resistance of the steering..

    Thus, if you are parking, or rock climbing...the pressure can get quite hi..1200psi in some systems

    If your running down the freeway and change lanes, 25-30psi might do it

    If, however, the "piston-seal" is worn out (or maby the spool valve)

    The PS pump will not supply enough VOLUME to compensate for the "by-passing oil", particularly at lo-rpm, and will need to be turned faster to make up...

    This will start at lo-rpm, (like when parking) and gradualy get to higher, and higher rpms as the piston seal wears
    --
    Bottom line;

    I suspect is is time for a PS gear box or rebuild

    /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  9. 74Chev

    74Chev 1/2 ton status

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    As stated in my post. Steering box is brand new. Working on this thing today. So far took pressure fitting and piston out. Cleaned the piston inlet screen, re-flushed system. Filled with fresh fluid, bled, started works better but still jerky at idle. I have had the pump out about 10 times at this point and have even swapped pumps, getting really pi**ed off. Fluid foams pretty fast and seems to get hot even with huge cooler. Is there something wrong with this new steering box, possibly the spool valve? /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif

    Any help much appreciated.
     
  10. the professor

    the professor 1/2 ton status

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    Sorry, missed the "new box" part...first line, stupid..
    --
    Jerkey at idle, and foam...sounds related
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    May still have air
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    Did you try jacking the front wheel up, and running the steering back and forth several times with it running..??
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    If it foams, might need to let it sit awhile
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    The Valvoline P/S fluid, is synthetic, and realy good..not your problem..recomended OEM
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    TRY and bypass your cooler...see if it makes a difference...
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    I have had some strange problmes with certain "spool-valves" and even a "slight" restriction on the box outlet...
    --
    Also, check your pump canister inlet..Its 3/8 hose fitting, but some taper down at the tip..drill or ream it out...
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    The "jerkey" part, could be a slipping belt(s)..They get "glazed" with age, and don't always make noise when they slip
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    Doesn't account for the foam
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    The foam sounds like it might be a bad pump..
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    There is realy no way to get air into the system, except through the pump shaft seal...even that seems unlikely...
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    Internal leakage in the pump maby, causing cavitation...
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    Is the little "O" ring on the end of the pressure valve there...??
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    If all else fails, try changing the fluid to ATF type "F" or "FA" and see if it makes any difference..

    ATF doesn't like the flash heat generated by the 800psi pressure of a P/S pump, but you do have a cooler

    This would be alot easier if you could take a pressure test..but even dealers don't always have the gages...
    - /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  11. BlazerGuy

    BlazerGuy 3/4 ton status

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    /forums/images/graemlins/confused.gif My brain hurts.... /forums/images/graemlins/grin.gif
     
  12. 74Chev

    74Chev 1/2 ton status

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    Re: Power steering problems continued (updated)

    Finally got the power steering pump problems fixed. Two AGR pumps, new gearbox, 7 qts of fluid and flushing chemicals, and 1 locally sourced pump and it is now working. The second AGR pump sent to me lasted 10 minutes and then the pump came apart internally. The shaft slid in and out about 1.5 inches (POS). Got a local high quality pump and installed the high pressure piston and outlet fitting from the AGR unit, worked better but still no power steering at idle. A fellow mechanic friend told me that once the high pressure line on his dodge had collapsed internally and would only have good assist at high rpm. I replaced the hose and put back the piston and fitting that came with the new pump and it fixed everything. After having to replace every part in my power steering system$$$ I am going to flush the system at least every 6 months now as this ordeal has been a real PITA. /forums/images/graemlins/mad.gif
     

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