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Discussion in 'The Hokey Ass Message Board' started by WINGOM8250, Nov 26, 2014.

  1. M8250
    Joined: Sep 23, 2010
    Posts: 37


    Running a 605 gear box and original chev pump in my 1961 Impala. Has anyone had any experience with either changing the 'flow valve" or adding shims to the pressure release valve?? Thanks Mason
  2. L. Eckart
    Joined: Jul 8, 2005
    Posts: 405

    L. Eckart

    I haven't changed the flow valve or shimmed the release valve but I did buy a pressure adjusting valve from Heidts and added to the 49 Chevy I recently sold. It was too quick and the Heidts valve solved the problem. Only thing I noticed was that at the adjustment I made for driving at highway speed it was more like manual steering at idle.
  3. oldolds
    Joined: Oct 18, 2010
    Posts: 3,056


    Cut a coil off the spring in the pump, or find a lighter one.
  4. ,,,a cut coil will make a spring stiffer,,,,,

  5. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,205


    I put an 800 Saginaw and unknown early GM pump in my 47 Frod truck. It steered way too easy - which made it seem "quick". I had done all the entire install so I knew the ratios were all good so I shimmed the pump by adding 1 shim. IIRC the factory had 2 - .030" shims in mine - I added a third - made a huge improvement. Easy to do - you can get shims from another pump - or just make them if you have a lathe.
    Now if by QUICK you mean the ratio - that is a whole 'nother kettle of fish. You may want to try a shorter pitman arm. I'm not sure about changing the flow - since I didn't have to do that on mine.
  6. HRBOB34
    Joined: Oct 1, 2009
    Posts: 337


    Borgenson makes a kit!
    It works well! Check there web site out!
    Joined: Jun 3, 2005
    Posts: 8,087


    Well since my 61 has this done and this topic came up, what's the favored PS pump to hang on the motor? Just whatever fits or is there a prefered application? Thanks in advance, didn't intend a hijack, thought it to be a good place to find that related info.
  8. Atomic Kustom
    Joined: Feb 5, 2010
    Posts: 211

    Atomic Kustom

    Use the flow valve shim kit from Borgenson, it is the correct way to reduce the pressure in the pump. The kit is cheap and comes with full instructions. NEVER CUT THE SPRING.
  9. retromotors
    Joined: Dec 10, 2008
    Posts: 1,045


  10. 4woody
    Joined: Sep 4, 2002
    Posts: 2,101


    From Crankshaft Coalition:

    Steering "feel"
    If it is simply too “light”, “soft”, or “over responsive”, you may want to address the flow and pressure differentials between RB and R&P.

    [edit] Pressure relief valving
    Most older GM pumps will have a pressure rating as high as 1350 psi. The '82–'94 Chevy S10 has the lowest rating at around 1100 psi. The Cavalier rack was designed for a pressure of ~1,000 psi. You can adjust the pressure with a simple shim kit from Borgeson.

    The pressure relief valve is located behind the high pressure output fitting on the back of the pump. You may need a small magnet to pull it out of the recess. The shim kit comes with a tool to help with removing the end nut, a new O-ring for the outer fitting, and several shims with a guide on how many shims to use to attain the desired pressures.

    Basically, adding shims reduces the pressure on the spring, allowing the bypass to open sooner and recirculate the fluid, rather than force it to the rack- thus making the pressure lower. The kit allows for reduction to about 750 psi, suitable for a Mustang II rack, which allows you to get well below the normal range for a Cavalier rack. Reduce the sensitivity to what suits you. In most cases, the pressure reduction valve can be removed and replaced with the pump in the car. Yes, you have to drain and refill the pump each time, but that’s pretty minor.

    [edit] Flow rate
    The second adjustment available is flow rate. The flow rate is determined by the size of the hole in the high pressure fitting (the one you took out to get to the pressure relief valve) on the back of the pump. The earlier pumps had an output hole of 5/32". The Cavalier pump has an output hole of 1/8" (approximately 20% smaller). I could not find a fitting with the smaller orifice to fit the older pump (newer GM pumps use metric fittings). Perhaps if you start with a later S10 pump, metric might not be an issue- but this needs to be confirmed first. As an alternative, it was fairly simple to weld shut the orifice in the original fitting and re-drill it to 1/8".

    Note: The experts contend that reducing the pressure will reduce the amount of assist provided, which can be reduced below factory specs to give it a heavier feel. The system is designed with a variable ratio, that is, it is designed to give more assist the further you turn the wheel, like for parking maneuvers, etc. You can't harm it by providing less than factory pressure. The flow rate seems to be more of a factor in the sensitivity over center, where you really don't need any assist. In any event, both changes were noticeable from the original test drive.


    High pressure hose fitting from the back of the power steering pump

    Weld or braze, then re-drill the center hole to change flow rate, not the side hole
  11. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284


    "Pressure is Pressure" and "Volume is Volume"
    Pressure controls how light it feels, Volume controls how quick it turns.

    The pump should be running on bypass all the time, so if the steering is too quick you need to restrict the flow [ the most flow you'll ever need is "lock to lock" parallel parking at idle]

    From experience with a few Power Steering conversions using Japanese 16:1 steering boxes, they have little "reel" shaped restrictors in the hoses. [1 on power ,2 on return]
    These restrictors are hidden where the hoses clamp to the inner fender/chassis.

    Racers LOVE braided "bling bling" hoses, so they make a mistake of removing the restrictors, then they go chasing their tail modifying the pump and steering box to fix the situation.

    On my car I reduced the pulley speed to the point where I needed to blip the throttle to reduce a shudder cause by low pressure at idle.
    My car was constantly in the 5000-7000 RPM range so it reduced aeration of the fluid bypassing in the pump

    "Run factory hoses to match the pump"
  12. junkyard junky
    Joined: Jul 19, 2005
    Posts: 1,099

    junkyard junky

    I used the Borgeson shim kit on my 62 Bel air wagon. Ordered a 600 Delphi gearbox from them and I've had nothing but problems with the steering. Three washers were used on the pump and there was already one on there. Mine was a factory ps steering car but all the original stuff was leaking and worn out. Borgeson keeps saying I need more caster but I'm not sure how much more I can get after adding ridetech upper control arms. Can get the car to about 50 mph before its hard to control. When I hit a dip in the road the car wants to take off in either direction.
  13. DPDISXR4Ti
    Joined: Jul 8, 2011
    Posts: 12

    from New York

    Bumping this thread as it's got a good post above (Thanks 4Woody!) on the two different approaches to modifying a Saginaw P-series, remote reservoir, pump. One approach focuses on pressure, the other on volume. I'm wondering if the high pressure fittings are cross-compatible between the later Type II (TC) Saginaw pumps and the P-series. I'm planning to use a metric P-series, but want to have lower volume, so I'm hoping to be able to just use a pressure fitting from a Type II pump. They're used on all sorts of cars - even Ford uses that pump after finally giving up on the noisy C2 pump they used for years.
    Last edited: Mar 7, 2019
    Joined: Oct 22, 2017
    Posts: 112


    or try a smaller steering wheel
  15. scrappybunch
    Joined: Nov 16, 2011
    Posts: 335

    from nj

  16. DPDISXR4Ti
    Joined: Jul 8, 2011
    Posts: 12

    from New York

    Interesting article. Only problem is, the options discussed there only apply if you're staying in the GM family. I'm looking to use a pump from a Chevy Astro van in a European Ford (Sierra) with a Subaru Brat pickup bed on it.

    If I find the answer to my question I'll update this thread (unless someone else wants to beat me to it).
  17. saltracer219
    Joined: Sep 23, 2006
    Posts: 773


    This is just a little O.T. for a traditional Hot Rod forum!
  18. DPDISXR4Ti
    Joined: Jul 8, 2011
    Posts: 12

    from New York

    Been digging back into this project and found that I had stowed away a ~2001 Saab 9-3 power steering pump (p/n 5061841). This is type II pump which uses flow/pressure fittings which are compatible with the P-series pumps. The orifice on the flow fitting is ~3/32", a bit smaller than even the Cavalier pump mentioned above. The overall length of the pressure relief valve is 1.382" vs. 1.375" for the P-series pump out of the Chevy Astro. I'm going to give this a try and see how it works out.
  19. DPDISXR4Ti
    Joined: Jul 8, 2011
    Posts: 12

    from New York

    It works! And it works well! i.e. Not whiny, and not too much assist, which is something I was concerned about since GM power steering is often too over-assisted, so you loose road feel. It think it was the Saab 9-3 volume regulator that helped the most in that regard. Before I forget everything, here's what the build consists of (listed in one place).

    XR4Ti power steering pump bracket, clearanced for Saginaw pump and adapter horseshoe
    ~2000 Chevy Astro power steering pump $15
    ~2005 Chevy Trailerblazer 4.3 pulley
    Edelman Power steering pump rebuild kit (p/n 7918) $10
    PSC Saginaw pump adapter bracket (p/n PSC-MB03K) $30
    Saab 9-3 Pump Volume and pressure fittings (only)
    XR4Ti Hi-pressure hose - bottom half
    Saab 9-3 Hi-pressure hose - upper half
    3/8" barbed fitting to create new hose $5
    40.7" / 1035mm Microgroove belt (p/n's 6PK1035, 407K6MK , 5060407) Technically NOT a stretch belt, but I was able to maneuver it on
    Volvo Power steering reservoir (small, square black unit)
    Saginaw-Fitment-1.JPG Saginaw-Fitment-2.JPG Saginaw-Fitment-3.JPG Saginaw-Fitment-4.JPG Saginaw-Fittings-1.JPG Saginaw-Fittings-2.JPG

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