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Thread: eps steering rack.... delvin into the deep!

  1. #51
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    getting back on track.......

    this looks somewhat better.....


    no clunking now.....

    one thing i did note.... there wasn't any dowels/location for fitting the ball screw mount to the motor when assembling the rack... there's holes through the various components (motor bearing mount, ball screw mount and end cover) so some pins were made up to align during assembly, and make sure there was no looseness/backlash between the motor and ball screw gears.....

    one side was a small hole....
    IMG_20190316_140618 by jon sutherland, on Flickr

    the other side was a larger hole through the top 2 items, but a flatted hole cast in for the motor bearing plate....
    IMG_20190316_140628 by jon sutherland, on Flickr

    just to be awkward, so a pin was tweaked at the end.... ok, probably overkill, but, anyway, no backlash and everything moving fine!

    re. the passenger side bush.....
    IMG_20190316_141125 by jon sutherland, on Flickr

    .....i decided to leave it as is for the time being, the play was minimal before i stripped it, and a good grease will lose that.... so i put the circlip back in.... btw.. if you get a 'knock bush' it'll just go in to the slightly larger stepped end (ironically circa 27mm, you know, standard industrial bearing size!!!)

    so the rack is buttoned up and complete with new rack end knuckles, gaiters and steering ball joints! it's smooth with no knocking, brushes rattling or play anywhere. it's slightly stiffer, but that's down to the motor bearings now being new and tight, rather than 150k miles old rattly ones! i'll just have to be careful on the first few drives, making sure the self centreing is ok (a D1guy scare story on one of his messages! along with various references to 'bushings' when meaning 'bearings'!)

    i can push the steering rack by hand, so steering geometry doing it should be fine!



    ....now i can get back to other stuff!!!!
    aka Jonathan!!

    '92 charlotte green auto.... as a daily
    '37 Ford Y street rod......... something for the weekend!

    ...... if a photobucket pic is foggy, click it, and it'll take you to the clear version, yes, it's a clicking faff....

  2. #52
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    as it was a pleasant day i got a chance swap in the steering rack....

    ! started at about 10:15....
    IMG_20190330_101753 by jon sutherland, on Flickr

    once i had the car on the front axle stands, i fashioned a simple tracking gauge to mark the current alignment (a laser pointer taped to a stick that sat against the front wheel edges, and put a dot on a bit of tape stuck on the rear wheel, when marked, this gave me a reference to get everything basically in the right place with the new/old rack!)....i also marked the input shaft and seal to show me where the exact centre point is!

    .....and an hour later....

    IMG_20190330_111942 by jon sutherland, on Flickr

    and another hour and a half it was all back together....

    pleased to say it's all working as it should, no play, slack spots, tight spots, or anything else untoward! took it out for a test drive, wary of the 'won't self-centre' scare comments, and all was well, no knocks or unusual noises!

    so, if you have any of the mechanical symptoms, they are, touch wood, cureable, as they are essentially a basic mechanical system that's just bearings and gears!!
    Last edited by britlude; 07-04-2019 at 07:48 PM.
    aka Jonathan!!

    '92 charlotte green auto.... as a daily
    '37 Ford Y street rod......... something for the weekend!

    ...... if a photobucket pic is foggy, click it, and it'll take you to the clear version, yes, it's a clicking faff....

  3. #53
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    update, now its been in a week....

    when i put it together, i set the preload clamp bolt ( the one that presses the rack onto the input shaft) as per the honda service manual instructions, tighten to 4nM, release, do it again, back off 20 degrees and tighten the lock nut.

    the weight on the input shaft was then checked as per manual at 3Kg at 100mm lever length (ie. gently clamp on some grips on to the input shaft, measure out 100mm from shaft and pull at that point with a spring balance...) so i double checked it was about that, it was, and fitted it all in....

    if this is how it's supposed to be, then no wonder auto cars get a bad press with 'dull' steering.... it's like driving in treacle.... yes it all does what it's supposed to but its heavy going.... i expected it to be tighter, as there's more drag on the shiny new motor bearings, but the motor assist will offset that...so a bit more investigation....

    the eps rack, according to the service manual is set to a load of 3kg on the 100mm lever....
    the manual rack is set, according to the book, at 1.5kg... so it's half the turning force when there's nothing connected to start with!

    i then checked the rack i removed, which was comparable to the original rack when i swapped it in..... 0.7kg!!! no wonder Sarah thought it was really light when she drove it!

    fortunately the rack clamp bolt is easily accessible under the car, so a quick jack up, back off the lock nut, do the double torque up, and back it off about 40 degrees, check there's no play or issues, there's not, so all back together... i did a spring balance check on the steering wheel before and after, and i suspect i'm closer to 2kg/100mm now, not as loose as the manual rack, so splitting the difference!

    the result, much nicer

    so, lost the knock going over bumps, the other rack had a small dead point when you rocked the steering (probably a combination of the torque sense mechanism getting sticky and play in the ball screw mount as well and hence this whole investigation) so obviously lost that, and lost a 'knock' from the input shaft every 360 degrees (probably that loose plastic gear related)

    so that's the steering rack sorted!

    ...and i've got the one i took out to go through too..... at my leisure!!
    aka Jonathan!!

    '92 charlotte green auto.... as a daily
    '37 Ford Y street rod......... something for the weekend!

    ...... if a photobucket pic is foggy, click it, and it'll take you to the clear version, yes, it's a clicking faff....

  4. #54
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    All thumbs up for the work, I'm truly, truly impressed!

    PS: My rack got serviced at KSP when the car was still in Japan (google translator version of their procedure here).
    1997 JDM Custom Order AT VIN 1400005 - Stock
    Heineken's Garage

  5. #55

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    I'm also impressed and want to thank you for sharing this with us. Can I ask for comment on my power steering?
    Its a 1991 UK car,all original. When I bought it I thought the steering was heavy when cornering at moderate speeds,but felt fine whilst parking. I read an old 1991 Motor Sport road test,"The steering felt light and deft whilst parking but any kind of cornering effort felt so heavy that we thought the power steering had failed. Over a thousand miles it became less disconcerting....."
    Car magazine in 1997 said that "at speeds of more than 87mph assistance is virtually nil"
    Has anyone else had similar experience and is there any adjustment possible?

  6. #56

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    Quote Originally Posted by pralognan View Post
    I'm also impressed and want to thank you for sharing this with us. Can I ask for comment on my power steering?
    Its a 1991 UK car,all original. When I bought it I thought the steering was heavy when cornering at moderate speeds,but felt fine whilst parking. I read an old 1991 Motor Sport road test,"The steering felt light and deft whilst parking but any kind of cornering effort felt so heavy that we thought the power steering had failed. Over a thousand miles it became less disconcerting....."
    Car magazine in 1997 said that "at speeds of more than 87mph assistance is virtually nil"
    Has anyone else had similar experience and is there any adjustment possible?
    If your car is a totally original 91 manual transmission NA1 then you DON'T have power steering.
    Electric power steering was only fitted to auto transmission models but from 1995 all NSX's except R's were fitted with it.
    Hope this helps.
    Pride.

    1992 My beloved Red/Black manual NA1.😎
    1992 Chevy Lumina apv Rockford Fosgate sound system demo van.🙉
    2003 Hartge Mini Cooper S (2 x UK & 1 x European sound quality finals winner) 🏆 

    "The NSX's greatest victory was to WIN the 1995 Le Mans 24hr GT2 Class"
    ..............and guess what, it was a RED one but of course.  

  7. Default

    Quote Originally Posted by Pride View Post
    If your car is a totally original 91 manual transmission NA1 then you DON'T have power steering.
    Electric power steering was only fitted to auto transmission models but from 1995 all NSX's except R's were fitted with it.
    Hope this helps.
    IIRC the 1991 Motor Sport review was of an auto; the 1997 car reviewed by Car magazine would have had EPS. If you do have a 1991 manual, these comments are not applicable to your car.

    However, if you do have a 1991 auto and therefore have EPS, that experience sounds normal.

    The steering is set up to have more assistance the slower you go. As such parking is easy, but yes, steering loads will increase significantly at higher speeds.

    I've seen several different speeds quoted for the point at which assistance is effectively switched off and I'm not sure which of them to trust. My car (1995 manual - see above) certainly feels like assistance switches off a long way below 87!

    As regards tuneability of assistance, no idea. Per the OP's adventures there is some tweakability, but adjusting the speed at which the assist comes in and out sounds like a different challenge.

  8. #58

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    Thanks for your responses. Yes my car is automatic,so I tend to follow Britlude's adventures.

  9. #59
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    Don't want going off topic with Jonathan's thread but I felt good place for the EPS reference so here is what I felt.


    For your reference, with JDM, EPS was available as an option on MT model since 93.


    Honda did modify the hardware and software on many occasions especially on the controller side but broadly speaking, there are two spec on the EPS rack and (sort of) three spec for the controller side.
    Depending on the combination, you will get different feeling.


    Definition:
    Rack A: With rotational sensor + torque sensor, up to 96.

    Rack B: Only with the torque sensor, WITHOUT the rotational sensor, 97+.


    Controller I: The original two separated boxes (power and controller), 91 - 94.
    (Strictly speaking, 91-92 controller was only designed to communicate with the AT controller whereas 93+ one could be used not only for AT but also on the MT model through pulser unit so some differences but for the ease of explanation, going to treat them as the same two box style).

    Controller II: One box solution, power and controller all in one box, requires both the rotational and torque sensor input, 95 - 96. (Can't be used with Rack B explained later.)

    Controller III: Same one box solution as spec II, only requires the torque sensor input, can be used with both the Rack A & B, 97+.


    My personal feedback (could be different from yours depending on the chassis setup, etc):

    Rack A + Controller I:
    Your feedback is probably spot on.
    The power assist suddenly disappears (more like On/Off feeling) at around 30 - 40mph.
    You can feel this sudden loss of assist.

    Also, when you turn the wheel while moving the car to position it on the lift, you can feel tiny delay in the assist response.
    Hard to explain the feeling but basically, you turn the wheel just a tiny bit but you don't get the assist immediately and like 0.2sec later, you feel some sort of 'knock' through the steering wheel as the effect of initiating the power assist.

    For the clarification, this 'knock' is different from the one you will get when there is a small play at the metal bush inside the EPS rack (as you can see in Jonathan's video) or the click/knock that can happen if your universal rack joint is loose.


    Rack A + Controller II:
    The power assist is much more changed smoothly/progressively and almost no assist around 50 - 60mph.
    There is still the response delay as described above.


    Rack B + Controller III:
    The best combination.
    Again, smooth reduction of power assist as above and felt like even better over A + II but back to back test was done against A + I so it could be my imagination.
    Still, the power assist changes are very smooth.

    And the biggest difference is the response time.
    From time to time, I have two NSX with EPS, one with 97+ and the other the pre-97 AT or MT EPS model.
    There is no delay in assist response with 97+ that you could feel on the 91 - 96 EPS models (A + I, A + II).



    I haven't tried the combination such as A + III so can't comment on this.

    Honda did modify the hardware mainly for the reliability issue for the Controller II & III many times so my feedback may not cover all of the spec.

    Also, the chassis setup especially the tyre and F/R rake would change the feedback dramatically so may not be the same for your spec but at least, hope you can get some idea on the differences over the EPS generation.


    Kaz
    Last edited by Kaz-kzukNA1; 07-08-2019 at 02:44 PM. Reason: extra info on 93+ controller

  10. #60

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    Quote Originally Posted by Kaz-kzukNA1 View Post
    I haven't tried the combination such as A + III so can't comment on this.
    Thanks for the detailed information on the EPS setup. My NSX is a 1993 EDM 5MT with EPS and the delay on the assist become more noticeable when i changed to the Type S steering wheel (expected as the steering wheel is much lighter and will let feel the transition better), to the point i thought something was wrong with the EPS.

    When driving the car this delay is not a problem, only when parking the car or maneuvering at very slow speed I can definitely feel it

    If association of rack A + controller III could improve the response time I would try this for sure... someone must be the guinea pig... maybe me... if i can source a 97+ used controller at a fair price... would this be P&P? (since we go from 2 separated boxes to 1 box)
    Last edited by bbvnsx; 07-08-2019 at 11:23 PM.

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