Power Steering Pump

Discussion in 'Gen 1 & 2 - Suspension, Brake Systems, & Body' started by sperold, Jun 2, 2019.

  1. sperold

    sperold Last to Know Supporting Member

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    Does anyone know how much pressure a GenI power steering pump generates.
    Just generally, and does it change much with RPM.

    Trying to stop a leak in one of the 2 directional lines on the rack, and would like to know what I am up against.

    Thanks
     
  2. NoSlo

    NoSlo GoldMember

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    Here's what you're up against. Either replace a seal or replace the hose.
    [​IMG]

    No idea the actual pressure, but RPM affects the flow rate, you can see this in the return line and swirling fluid of the reservoir. The "piston" has perhaps 1 square inch of area or less, so it likely directly translates pounds per square inch <-> pounds of assist force.

    My guess is that pressure is only built when you turn, the power steering gear restricts the flow and directs it to assist, and you can hear this work in a power steering pump whine just when you turn, especially when you hit the stops.

    The return transfer tube should have little pressure. For the input and output hoses:

    "The gear incorporates quick-connect fittings for the pressure and return lines that allow the lines to swivel. If the fittings leak, check to ensure they are tightened to 10-15 ft-lb (do not over-tighten) (ed: it also says 10-20 elsewhere). If the leak is not corrected, replace the fitting seals.

    Here is that seal, #36 seals below. Ford part is 388898-S.

    [​IMG]

    PS ignore this diagram if you have VAPS, that rack is non-serviceable, even to put a new seal in the end.
     
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  3. sperold

    sperold Last to Know Supporting Member

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    Thanks so much for the parts description.

    The lines 40 H and 41 H are exactly what I am talking about.

    It seems I either need to tighten the outer nuts or install new small seals.

    And there is always a chance one of them has rusted out.

    As soon as the temperature gets a bit more above freeing, I will be putting it up on the ramps and figuring it out. Oh, and it rains every day now, so that makes it even better.

    Thanks again !


     
  4. blk\blk90

    blk\blk90 SHO Member Supporting Member

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    So with the connection to the steering shaft on the drivers side, what can leak on the pass side and burn off/drip on the subframe mount? Is that where the lines are?
     
  5. NoSlo

    NoSlo GoldMember

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    On the subframe bushing, chances are better that it is a piston end seal, because of course that is a wear part that takes removal and partial disassembly of the rack and special tools...

    An end leak shouldn't make its way to hot exhaust, though. It will just dissolve your bushing to mush.

    You can see if the inside of the boot is dry when you do your inner tie rod end that you haven't thought about for a while. Or if you can dump out red from the bellows. If so, you can hope AutoRX does what others have attested in softening the seal. Steering stop leak in a bottle is not compatible with Type F.
     
    Last edited: Jun 5, 2019
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  6. sperold

    sperold Last to Know Supporting Member

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    My issue is where the 2 lines come out of the rack assembly on the drivers side and turn 180 degrees.

    When you take the drivers side tire off and look through the inner fender, you can see the fitting(s) nut which start out dry, slowly get moist and turn into a droplet, which drops off when another one forms.
    I have to get some help and have them turn the wheel slightly to see which is the offender.
     
  7. sperold

    sperold Last to Know Supporting Member

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    Put the car up on front ramps and it turns out it is the short line that leaks at the fitting. That is the one that assists when you turn right.

    I can barely see the line and fitting, let alone get a wrench on it. And the lines don't look like they would respond well to being moved around.

    I was thinking that the underneath look would be a big benefit, but I was wrong.
     
  8. sperold

    sperold Last to Know Supporting Member

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    Thanks again for this pictorial diagram.

    Would you or anyone else have the part numbers for items 40 H and 41 H on this diagram (the fluid transfer lines on the rack itself).
     
  9. NoSlo

    NoSlo GoldMember

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    Did you not have luck with teflon seals? They need to be stretched over a cone to size (and get softer in hot water) and then quickly installed on the fitting.

    The part no appears to be:

    40H - Transfer tube assy, E4DZ-3A714-A (discontinued)
    41H - Transfer tube assy, E4DZ-3A717-A (discontinued)

    [​IMG]

    No cross to any other OEMs, and the second part # only has a scammy looking site selling it. I expect that remanufacturers of racks have a source, if they don't simply have their own pipe benders. Tranny shops can often make this kind of tube, but the fitting looks unique.

    You can look to u-pull wrecking yard sources, there's an 89 Taurus near me, for example, that won't have VAPS.
     
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  10. sperold

    sperold Last to Know Supporting Member

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    Yes, the teflon seals are available in sets of 2 or a package lot of about 6 or so.

    That is what gives me hope that the lines are out there somewhere. The fittings do look unusual, and that is what is making this difficult.
     
  11. sperold

    sperold Last to Know Supporting Member

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    I was not able to find any lines on the internet, anyone who sold them previously has run out of stock.

    I believe the tube assembly is sold like brake lines; you get the tubing and the 2 ends captured on the tubing, and it is a straight length, you have to bend it to shape. These part numbers represent lines of a certain length with these Ford type ends attached.

    I came to this conclusion by checking what else these lines fit and checking the pictures of the rack. Ours exit the rack on the the drivers side and turn 180 degrees to travel back along the rack, Other configurations show the lines exiting the rack facing straight ahead towards the radiator (Tempo), so a pre-bent part could not fit both conditions.

    Since I doubt I could bend that 180 degree bend close to the threaded adapter, finding the part may not have been a help.

    If I could figure out the thread size, I think I could make something up using right angle fittings from a company like Parker Hannifin or Swagelock.

    Thanks for listening.
     
  12. sperold

    sperold Last to Know Supporting Member

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    To answer this thread's first question, the SHO pump is an Atsugi; and the minimum to maximum relief pressure is 1400 to 1530 psi.
    It has a maximum flow rate of 2.8 gallons per minute at 1500 rpm.

    As impressive as these numbers are, they are almost identical to the 3.8 model pump and only a bit higher than the the 2.5 and 3.0 pumps.

    The thing I find puzzling is, if the relief pressure is as high as reported, what protects that little plastic reservoir and the flex hoses associated with them. What keeps some of that pressure from ending up in that supply system? The return line from the system ends up in the reservoir.

    This information is to round out the experience of anyone searching the forum in the future that wants to know something about the pump.
     

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