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Technical Power steering pump issue

Discussion in 'The Hokey Ass Message Board' started by RMR&C, Nov 26, 2021.

  1. I had to replace the PS box on a '49 International, it was converted to PS by a previous owner. Now the pump is whining loudly, leaking around the pressure port and spitting fluid out the vent in the cap. Pump seemed to work okay before I took it apart.
    GM PS pump(70's?) GM saginaw PS box of similar vintage. Fresh Dexron atf fluid.
    Fluid is foamy , wondering do I still have air in the system somewhere. I cycled the steering back and forth several times to get the air out, steers fine but still whines. What am I missing?
     
  2. cycle the wheel lock to lock a gain... several times.

    Or try this..

    DAS20008L__21508.1622725657.jpg
     
    Bob Lowry likes this.
  3. What do you mean “ took it apart”

    foam, noise , leaks …. It’s sucking air or bypassing internally
     
  4. Removed the hoses to swap the steering box. I also dumped the old fluid and replaced with new.
     

  5. greybeard360
    Joined: Feb 28, 2008
    Posts: 1,848

    greybeard360
    Member

    Let it sit for an hour and start it back up. Cycle it lock to lock holding it there for a few seconds. Shut it off and repeat. That usually get the air out. You can also apply vacuum to the cap and get the air out but that means taking a second cap and drilling a hole in it to use the nipple from a hand vacuum pump.
     
    RMR&C, VANDENPLAS and seb fontana like this.
  6. Jethro
    Joined: Mar 5, 2001
    Posts: 1,618

    Jethro
    ALLIANCE MEMBER

    Hey Scott I've always cycled PS pumps with wheels off the ground , seems to work give her a try.
     
  7. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,132

    TrailerTrashToo
    ALLIANCE MEMBER

    About 20 years ago, I had a rebuilt PS pump (A1CrapDone - Made in Mexico) that had those symptoms. Returned it for another rebuilt that was somewhat quieter. Many years later, I had the PS pump professionally rebuilt. The rebuilder found that some of the vanes on the pump were randomly installed with the tapered edge backwards.

    Any chance that the tapered edges got installed facing the wrong direction?

    Russ
     
    MAD MIKE likes this.
  8. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 694

    MAD MIKE
    Member
    from 94577

    A simple trick I've found that works when trying to prime a PS pump is to fill it and then rotate the pump backwards, it will spin really easily and then it will drag a little, rotate it normally by hand you should feel some resistance.

    Do you recall how you put the vanes back in?
    Vanes will have two ends, one side will be square like the sides of the vanes, the end will be rounded.
    If the rounded ends are not facing against the cam ring, it won't seal/pump properly.

    GM Saginaw pump parts.jpg
     
  9. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 694

    MAD MIKE
    Member
    from 94577

    A note on fluids.
    These pumps were designed for ATF(Dexron/Dexron variants) don't use gear oil(too thick), goos(sealers/stop leakers), or the 'light' gear oils passed off as 'power steering fluid'. Anything other than ATF is gonna gunk them up at best or possibly even cause cavitation(damage) to the pump components from incorrect viscosity.
     
    RMR&C likes this.
  10. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,203

    Mr48chev
    Member

    Never put Dextron in a GM power steering box. I probably flushed 100 of them and replaced the fluid with Genuine GM power steering in the years I worked in Pontiac dealerships.
    I don't care what the self style experts say on this one I have done too many of them.

    Flush it out, put the correct power steering fluid in it and go from there. You may have already galled the vanes against the cam ring or pressure and thrust plates though.
     
  11. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 1,132

    TrailerTrashToo
    ALLIANCE MEMBER

    No Further Information (NFI ;)) - The final rebuild was done by Benchworks in Scottsdale, AZ. I got several flawless years out of it - The truck was rear ended and totaled.
     
  12. 03GMCSonoma
    Joined: Jan 15, 2011
    Posts: 279

    03GMCSonoma
    Member

    I have used Blue Devil Power Steering Stop Leak on my '38 Chevy. I believe just about any stop leak would work for you but, obviously, some work better than others.
     
  13. Thanks for the replies. The leak is likely a separate issue....I'll re check the fitting. Using ATF for fluid.
    I'll try it again and see what happens..
     
  14. Personally I use ATF in my transmissions and power steering fluid in my power steering pumps. Good luck eliminating the problem.
     
    gimpyshotrods likes this.
  15. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 694

    MAD MIKE
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    from 94577

    427 sleeper likes this.
  16. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,610

    Elcohaulic
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    RMR&C likes this.
  17. Ralphies54
    Joined: Dec 18, 2009
    Posts: 755

    Ralphies54
    Member

    Weren't some of those pumps reverse rotation for cars with serpentine belts?? Maybe you got the wrong pump!!
     
  18. Tried again, still not working right. I have another pump I can swap in, then tear this one down at my leisure. Thanks for all the feedback.
     
    TrailerTrashToo likes this.
  19. The foam could be caused by a leaky shaft seal pulling air in. Smear grease around the shaft/seal interface and see what happens. Do this after it has been sitting long enough for the foam to subside, and before you start it up. Also check around the return hose for an air leak. It could be bypassing over a stuck relief valve too, although from the parts diagram I can't tell where that's located, unless it is part of the "flow control valve".
    Good luck!
     
    RMR&C likes this.
  20. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 694

    MAD MIKE
    Member
    from 94577

    Only the water pumps were reverse rotation.
    Backside of the belt routes over the WP pulley backwards in an 'S' shape.
    Note the belt wrapping of the A/C, Alt, and PS. They will rotate normally.
    WP, tensioner and idler pulley are run off the smooth backside of the belt and will rotate backwards to the crank.
    GMPM serp belt routing.png

    Cam ring inside the pump does have an arrow on it, not sure if flipping that would turn the typical PS pump into a 'reverse' rotation pump.

    If the PS pump was sitting on the shelf, assembled dry:eek:, or assembled incorrectly it would not function properly.
    Also when priming the system it's very easy to over do it.
    I normally just fill the Spam can with fluid, rotate it by hand a few times to note if there is any resistance change. If so I know fluid is getting to the vanes. Start the engine and let it idle.
    Lift the front wheels off the ground. Observe the fluid if it is not aerating and no leaks. Then simple turn the steering wheel 90° to the left and let it sit. Look for bubbles. Then turn the steering wheel 90° to the right and let it sit. Look for bubbles. And let the system bleed. If no bubbles, verify fluid is still full, top off if needed, and then rotate to full lock Left, look for bubbles, let it settle and then turn to the right, look for bubbles, let it settle.

    What you DON'T want to do is start up the engine and then immediately crank it to hard LEFT/RIGHT and hear the pump whine. That is causing the pump to max pressure. It doesn't do anything to help bleed and can cause aeration, which will take longer to bleed the system.
     
    TrailerTrashToo, Ralphies54 and RMR&C like this.
  21. seabeecmc
    Joined: Jan 28, 2005
    Posts: 1,074

    seabeecmc
    ALLIANCE MEMBER

    DEXTRON is still alive?
    DEXTRON is still alive?
     
  22. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 1,421

    Barrelnose pickup
    ALLIANCE MEMBER

    Elcohaulic likes this.

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