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Steering U-joint Question

Discussion in 'Builds and Fabricators Forum' started by FinoCJ, Oct 18, 2021.

  1. Oct 18, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    I feel like I've read on either the Ididit or Flaming River sites that an a carrier for the steering shaft is often needed when more than 2 u-joints are used in a set-up. Does a double joint count as 2? I am hoping I can get away with 2 single joints (one at the base of the column and one at the steering box that replaces the rag joint), but the upper joint will be right about at the max limit for angle. It seems if I put a double joint there, the steering starts to get wonky - thus maybe a shaft carrier is needed?
     
  2. Oct 18, 2021
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  3. Oct 18, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
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    I'm pretty sure you need a carrier.
    I remember a diagram that showed different arrangement when I did mine, but don't see it now.
    Check this and maybe you'll find something.
    Tech Tips (flamingriver.com)
     
  4. Oct 18, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Decided to try notching the motor mount and use a single joint between column and intermediate shaft, plus the one at the saggy box....I think this might work...
    [​IMG]
    [​IMG]
     
  5. Oct 18, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    How much clearance does one need?

    [​IMG]
     
  6. Oct 18, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
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    I have a small notch in my factory motor mount.
    I'd say 1/4" clearance should be adequate.
    Mine touches the exhaust manifold at extreme suspension flexure.
     
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  7. Oct 19, 2021
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    There's plenty of actual driveshafts with a double cardin on one end and a ujoint on the other, without a carrier bearing. I don't see why a steering shaft would be different. Make sure you have some type of slip joint though!
     
  8. Oct 20, 2021
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I would throw a 3rd U joint in there and add a support bearing similar to the 6th diagram on the chart. The angle of that joint looks a little tight for my liking when the chassis and body start flexing under normal driving conditions. It will likely wear out fairly quickly with that steep of angle. Added bonus, when you run 3 universal joints you do not need a collapsible section.
     
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  9. Oct 20, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Maybe it requires the angle of all the joints to be in the same plane or equally out of plane in opposite aspects, but when I replace the single joint with a double joint, the 2nd joint and lower shaft starts moving in a circle. Not surprising based on the borgeson and Ididit discussion, but just confirmation that its is needed for 3 joints.

    The lower steering shaft is a 3/4"-1" double D telescoping shaft. the 3/4" section goes to the ujoint at the saggy box which required a 30 spine to 3/4" DD joint. I think it goes 17-24" and I am somewhere in the middle of that range. In addition to safey, I just find it much easier to get stuff all installed and removed (which I have now down way too many times) with a slip joint.

    Its close to the limit for sure....I have a double joint that I can replace it with, but then the carrier bearing is needed of course. That can be done, but wondering more about the clearance around the motor mount. The double joint is longer will drop the shaft just a bit more, giving just a smidge more clearance, but its not really significant. If the motor mount clearance needs more, then its more what you describe, with a short section of shaft and another single joint (plus the support bearing).

    In ether case, I guess the support bearing would need to be mounted to the inside of the frame rail just behind the motor mount. How adjustable are those support bearings in terms of getting them positioned right - basically, are they length adjustable, or do I have to control that with the mount. Also, the shaft is not parallel to the frame rail, so how much angle can they work with? I know there is a sort of spherical/heim joint style bushing/bearing in it that I assume can accept a reasonable amount of off-angle?
     
  10. Oct 20, 2021
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    That U-joint angle isn't sharp at all compared to production stuff I've seen. Here's the angles on a vintage 911 and they don't have issues with U-joints wearing out prematurely:

    [​IMG]
     
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  11. Oct 20, 2021
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    Just like a driveshaft, make sure your joints are in phase, or your steering will speed up/slow down multiple times through a rotation.
     
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  12. Oct 20, 2021
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    In practice it doesn't seem to matter much for steering. Most rack and pinon cars have non-cv U-joints with non-matched angles/phases. You can't feel it at all when driving.

    Here's a typical example:
    [​IMG]
     
  13. Oct 20, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

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    Maybe the picture is a bit deceptive as its taken looking down and not showing the true angle from the side....I am more worried about the maximum joint angle and shaft interference with the motor mount than premature wear, assuming it just get sloppy and sticky etc as opposed to catastrophic failure at speed....Borgeson says maximum angle of 35 degrees (on a single joint) and when i was testing some different arrangements, anything at 35 degrees or so, and you can feel it bind and stick and jam up. The angle I have is just over 30 degrees on flat ground - it works fine as is, but its more a question of how much flex will occur. I am going to re-install the set-up as is and get a better angle measurement, and the maybe try jacking up different corners to see how it affects things.

    I don't know whether it 'matters' or not, but you can definitely see it when you watch it....it was a bit eye-catching, but I know I've driven some similar set-ups and never 'felt' it when driving.....
     
  14. Oct 20, 2021
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

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    I built my 3b steering out of phase back before the internet made it easier to research this type of stuff (and before I knew better), and I can definitely feel it, and it’s why it’s so front/center on my mind. The wheel in straight-ahead position is on the uphill side of a speed increase in the phasing, so just off straight, it steers much quicker one direction than the other. It’s frustrating.
     
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  15. Oct 20, 2021
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Just giving some information from production vehicles. You can spend a lot of time making it theoretically perfect but the OEMs don't bother because it's not worth the time/money to do so for them. At the end of the day you need to do what makes you comfortable with your own work.

    If you want it to be perfect, you should have a CV joint at the bottom of the column and try to have no angle on the front U-joint or use a rag-type joint there.
     
  16. Oct 20, 2021
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    there is very little angle at the bottom joint - it was a rag joint that I replaced with a u-joint as CW seemed to suggest that was much better. The box was mounted with the nose down more than any other I've have seen, i think specifically to accommodate the prior rag joint and keep the lower shaft straight into into the box - and it worked fine for the front cradle mount. But the side engine mounts are further back, and right in the pathway...by notching the mount, I am keeping the lower joint angle very small, and reducing the upper joint as much as possible. Its all a combination of trade-offs I guess....but I don't always know what I am trading off. I don't like gambling, and even less so when its blind.
    nothing makes me comfortable with my work - not enough experience to know, and too much of what I do only kind of works out right....Some future owner will definitely be making 'can you believe what the PO did here' comments!
     
  17. Oct 20, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

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    Remember that a steering shaft does NOT experience the rapid rotational speeds for which a driveshaft is designed.
    The sharp angles are probably fine with the steering shaft. Check for acceptable (smooth) operation before finalizing the location and mounting points.
    Keep in mind that some of the clearances will change with suspension flexure.
     
  18. Oct 20, 2021
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    From what I see in the photos, I think you're good to go with what you have done.
     
  19. Oct 20, 2021
    duffer

    duffer Rodent Power

    Bozeman, MT
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    The double cardan driveshaft joints have a spring loaded centering ball which is absent from any of the double steering joints I have seen. Without a support bearing, your alignment will vary (and possibly bind) with the double steering joints. I think James' layout is fine. If you can rotate it without binding you should be good. I think the clearance is good too. Alternately jack the front end up one side to the other until both wheels are clear. That should give you a pretty good idea on the limits of the frame flex and its effect, if any, on your clearance.
     
  20. Oct 20, 2021
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Correct, but with how much old vehicle frames and bodies flex the angle can easily create tight spots throughout the rotation. That is my concern and experience. I ran an angle similar to FinoCJ’s above and it wore out in 2 years.
     
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