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ToolBoy

Rear control arm bush alignment

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    I just ordered 55554-E4100, 55555-E4100 and 55541-E4100 and cut and burned out the old rear transfer link rubber bushings and I'm fixing to press in the new lower ones when I have 'em in hand. (nissanpartsdeal.com seemed to have the best price). The space between them obviously needs to match the corresponding width of the strut assembly but the FSM talks about aligning the two bushings so the spindle will pass thru as though they won't on their own. Can anybody share wisdom on this task?  Do I need to have the spindle temp- installed for alignment? Not sure what's happening here? Thanks.  Andy 

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    The few times I have done it I align the outside sleeve of the bushing with the control arm housing, that leaves the inside sleeve  sticking into the middle a bit where the strut mount fits into.

    You can leave more room on the inside for an easier install since tightening the 2 outside nuts will force the bushings to end up exactly where they need to be anyway.  It can be tricky getting everything to line up but resist the urge to hammer the pin through with anything harder than a rubber mallet or dead blow hammer, the threads on those pins are very soft.

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    Here's some discussion about the insertion of those rear outboard bushings in this thread:
    https://www.classiczcars.com/forums/topic/55369-1971-hls30-14938-lily-build/?page=2&tab=comments#comment-525861

    From that other thread:

    I also found a tiny bit of asymmetry with the rear spindle pin bushings as well. I don't know if it was designed that way, or if it was an accident, but I found a slight difference in the distance the metal collars stuck out of the new rubber bushings. One side was longer than the other, and all of them were consistent (as though it was done on purpose and not an accident).

    I put all four of them in such that the smaller distance was inward towards the strut body and the longer portion was on the washer and nut side. I found that with the bushing pressed into the center of the control arm receiving cylinder, the distance between the two bushings worked out to almost exactly the width of the strut knuckle casting.

    I found that if I reversed the bushings and centered them, I ended up with a gap where the strut knuckle fit. Of course, it was a small gap and would have easily clamped down as I tightened the spindle pin nuts, but I figured if I didn't have a gap in the first place, that would be better. Also, putting the longer end on the outside allowed more room for the rubber sealing washer.

    Don't know if all the aftermarket bushings do that, but I bought Raybestos 570-1030 - There are two bushings per box, so two boxes per car.

    If you squint right, you can see the asymmetry in this pic. See how the center sticks out farther on one side than the other:
    P1050378.JPG

     I found I liked the fit better with the short sides inboard towards the strut body.

    I found that if I reversed the bushings and centered them in the arms, I ended up with too small of a gap where the strut knuckle fit between the two bushings. Of course, since it's just rubber, I could have forced the bushing centers apart a little and forced the strut body between them, but I figured if things lined up naturally without having to do that, it would be better.

    With the small sides in, when I centered the bushings in the receiving cylinders in the arms, it worked out almost perfect such that the distance between the two bushings was very very close to the width of the strut housing. Seemed to perfect to be coincidental.

    So I don't know if they were really designed to be that way, but it worked for me. And if you're seeing the same small difference on  OEM bushings as I saw on aftermarket MOOG, then I'm starting to believe it really might be intentional.

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            Thanks for forwarding all this great info. Probably won't have the parts for a week but will read this all thru several times and then again while I'm doing it. Bearings and seals for rear stub axles are arriving today. I'm really hooked on the mustache bushing conversation and determined to find a better solution than the pu product at some point. Great that many others are interested in the same. My car was driven into the ground and then parked with the fluids in it for 18 years, fortunately in a garage in phoenix. There is absolutely no rust but everything else is shot. I just acquired a hoist and hope to pull the engine in next month to look at possible electrolysis damage, general condition and get fussy with the engine bay.

            Most of my Pa. memories are as a little kid. Moved from there when I was 12. Dad was a pretty well known architect in Lancaster. I used to pedal to the book store in the student union bldg. at F and M on a schwinn ram's horn fastback.  (Ha Ha) . . . From there to Corrales, New Mexico for almost 10 yrs. and then to L.A. area in 79. Been at same place on Palms in Venice since 97. Yes, we have probably crossed paths at some point. As artist Barbara Kruger said, "it's a small world, but not if you have to clean it"  

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    Hey Capt. Obvious,  Just finished pressing the rear control arm bushings a few minutes ago and wanted to say thanks for passing that info along 2 weeks ago. They went in perfectly and are spaced exactly for a nice press fit in the strut housing. Definitely would not want to back em out and do it twice. Thanks again!!  . . .  Andy

    CntrlBush01.jpg

    CtrlBush02.jpg

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    Excellent. Glad to hear they went in without incident.       :victorious:

    Out of curiosity... Did you find the same small amount of asymmetry in those outboard bushings that I did?

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    Yes I did. Put the short side in and strut housing spaced perfectly. Had to be designed that way. Was a great tip.

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    Than you make four out of four people now to support the theory of being designed that way. Thanks for the data point.

    Such a small difference though. It screams "oops" at the factory that they fixed by modifying the bushing.     LOL

     

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    The spindle is anchored in the center of the strut assembly by the bolt lock and then the arms / bushings, stoppers, washers and nuts stack on the spindle, forward and aft from the center. The "outsides" of the bushings in question that project a little further than the "insides" just accommodate the thickness of the rubber stoppers (55542) before end washers and nuts and assist the bushing in limiting fore and aft movement of arms while allowing everything to float and be dynamic and still stay centered. The smaller gap created by inside of the bushings allows just enough movement for the bushings against strut assembly without metal to metal contact.  Maybe the Tech illustrator missed the meeting and assumed the bushings were symmetrical so no instructions were provided when the service manual was written.     Or maybe it was like you said. . . "oops".

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    Yeah, I think someone missed a detail somewhere. Everything about the whole situation would make much more sense for the bushing to be symmetric. Assembly process would be foolproof because you wouldn't need to pay any attention to which direction it went in. and the documentation wouldn't have to mention anything about it because it just didn't matter.

    On the prototyping floor... "Hey Boss. I'm putting these bushings in and when I do that, I can't get the strut casting in between them. What are we going to do?"

    Boss says : "Hmmm... I'll let engineering know."

    Engineering says : " Oops. We'll need to either:"

    a) Change the strut housing design to reduce the width.
    b) Change the rear control arms to increase the span between the bushings.
    c) Change the bushing so things fit together without interference.

    And "changing the bushing is way cheapest and easiest to change, so lets do that."

    Draftsman/Designer says : "I can't shorten the outsides of the bushings because we need that length for the rubber washers. Should we eliminate the rubber washers and make the bushings symmetric, or should we make the bushings asymmetric and keep the washers?"

    Lead Engineer says : "Crap (in Japanese).  I really want to keep those washers. Make the bushings asymmetric and make sure you let documentation know about the change because they'll have to describe how to put the bushings in correctly!"

    And that last part never happened. I wasn't there for any of it, but that's how I see the whole thing.    ROFL

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    Aaaah. . . The forensic aspect of obsessively restoring and ultimately understanding a 50 year old sports car. Will be a real thrill to finally drive this sucker with what I'll  know by the time she's road worthy. 

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    I haven't tried this yet but some guys have started using 5/8" x 12-14" bolt instead of a $40 spindle pin. Using the rubber and steel washers as usual but with no need for the anchor/tapered bolt in the center.

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    Posted (edited)

     

    16 minutes ago, grannyknot said:

    I haven't tried this yet but some guys have started using 5/8" x 12-14" bolt instead of a $40 spindle pin. Using the rubber and steel washers as usual but with no need for the anchor/tapered bolt in the center.

    Many of the after market control arms that use 5/8 heim joint ends use a bolt like this. It’s a slightly loose fit in the stock application (stock pin is 16mm), just make sure you use a self locking nut and check it often. With no lock pin, if that nut falls off..... 

    Edited by zKars

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    9 hours ago, ToolBoy said:

    The forensic aspect of obsessively restoring and ultimately understanding a 50 year old sports car.

    LOL. I think I do a lot of that. Probably more than I should. Haha!

    Good luck with the project and hope it turns out well. My PO installed suspension was a total mess when I got my Z. I've since redone everything, and man.... Is it 1000 times better than before. Other than some steering wheel vibration at highway speeds (comes and goes), it's a pleasure to drive! 

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    4 hours ago, grannyknot said:

    I haven't tried this yet but some guys have started using 5/8" x 12-14" bolt instead of a $40 spindle pin. Using the rubber and steel washers as usual but with no need for the anchor/tapered bolt in the center.

    I've heard peopled talking about that in the past, and I'm not going to throw my body in front of anyone's train, but I think it's a bad idea.

    Clearance (gaps) are an enemy, and Carroll Smith says that bolts are strictly for clamping, not for anything else.

    I'm not a ME or a suspension expert, but I wouldn't do it. I've been known to substitute and modify stuff all over the place, but that isn't one of them.

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    Yeah, I think I'm in agreement with Captain Obvious on this one although I'm clearly a much less developed, lower life form that resides way down on the food chain . That very tightly fitted, locked in spindle pin is screaming "I'm done this way for a reason". If I ever need a new one I'll fork out the 40 clams and pack my lunch for a week.

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    . . . note to Captain Obvious. . . In my opinion (and my very, very personal, personal experience) the forensic analysis is what elevates it from 2D to 3D chess.  Identifying what the PO did and what aspects of that did or didn't work. ( and you get to berate him for it and be righteous which is always fun). The fact that you would imagine that Japanese conversation in 1969 is so awesome!!  I'm a finish carpenter and cabinet maker by trade and I've done a fair bit of structural wooden boat repair ( frames, planks, decks, garboards, shaft logs etc) and my favorite part is that analysis. I bought a 33 foot sailboat and when the glue-line broke on the 48 foot box constructed fir mast the PO stitched it up with stainless steel screws rather than ripping out the glue-line, cutting a spline and re-gluing. Potential point loading with a screwed joint on a flexible spar / bad idea. Figuring that all out is the fun part. (my opinion again)  

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    Posted (edited)

    I am always averse to changing an engineer's decision unless I know everything that went into the taking of that decision.  The problem is usually understanding all the loads and in this case, knowing how the spindle was specified, metallurgically. 

    If one were to remove the head and threaded end of the 5/8 bolt, they'd have a pin.  Could be a pin for a shear application, as most pins are.  It's fair to say, I think, that the failure mode for the spindle pin would be a double shear, or maybe a single shear with a moment.  Exactly the kind of loads pins are made for.  You can select the grade of that bolt/pin, 3, 5, 8, etc., and if you know the strength of the spindle pin, can do so to match.  Other than that you have to rely on anecdotal evidence, and the problem with that is you never know all the facts such as static loads, impact forces, installation details, etc. that the part has experienced.

    My favorite example.  Please bear with me a moment: We used to ship very expensive equipment upright, which meant it had to go by 747 freighter, which was expensive.  Manufacturing wanted to ship it on its back, something it was never designed for.  So one day they laid one on its back and shipped it somewhere and back again.  It came back fine (looking) and so they declared the equipment could now be shipped flat, since they'd proven it worked.  Scary.

    I believe we've all done things where we thought this will probably work, and it did!  Does that mean it's a good idea?  You'll never know.  All you can say is, "Well, it hasn't failed yet."

    Purely for the fun of it, I am making new pins on the lathe.  I too will be holding my breath for the first few miles. 😬

    Edited by ETI4K
    Added a point
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    21 hours ago, Captain Obvious said:

    Lead Engineer says : "Crap (in Japanese).  I really want to keep those washers. Make the bushings asymmetric and make sure you let documentation know about the change because they'll have to describe how to put the bushings in correctly!"

    And that last part never happened. I wasn't there for any of it, but that's how I see the whole thing.    ROFL

    Interesting that the section-view drawing of the installed bushing remains unchanged in the FSM's all the way from the 240Z through to the 280Z (i.e. shows a symmetric bushing and a rubber washer on both the inner and outer sides of the control arm pivots, making for a total of 8 rubber washers in the design).  The Parts Manual, on the other hand, shows the rubber washer only on the outer sides of the control arm pivots and states the number of rubber washers as '4'. 

    Given that disassembly of the rear suspension would have been a relatively common (and time-intensive) job for Nissan dealers' service departments, it seems curious that the service techs were apparently left to discover the asymmetric bushing design on their own and then correctly interpret the implications for correct installation.  I wonder if anyone has a photo of the Nissan OE part that would help verify that the bushing was assymetric right from the start. 

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    9 hours ago, ToolBoy said:

    and you get to berate him for it and be righteous which is always fun.

    No, not at all. I'm imaging a conversation like that because I've heard it a thousand times in the engineering department. You're rushing around near the end of a project and some little issue raises it's head... You have to make quick judgment calls between project schedule, cost, and result quality. It happens and I'm not berating anyone. I've been there many times!

    The only thing that really went wrong (in my imagined scenario) is the memo to the documentation group informing them of the change didn't make it. Or maybe even that did, but they decided that since they already had 10,000 books printed up, they would fix it in the next rev. And maybe THAT didn't happen.   LOL

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    Posted (edited)

    I’m not so concerned about the slightly sloppy fit of a 5/8 bolt as remember the strut and bushing core tubes are torqued together by the bolt/pin and locked solid to one-another.  The bushing rubber provides ALL the rotation at this joint. That’s why you torque this together with the car on the ground and driver weight in the seat. You want the rubber at its neutral position most of the time in use.  The locking cross pin provides a way to prevent the spindle pin from rotating while torquing (you can do either end independantly without using the other end as a backup) and is a fail safe in case all the nuts fall off.

    I also just inspected a half dozen old crusty control arms that still have the bushings installed to see where the center bushing tubes have come to roost left/right offset wise after years of use, to see if the initial offset made any difference other than assembly with the strut housing ease. What I found was a bit surprising.

    The front bushing clearly shows the center tube still offset toward the outside of the control arm, but the rear bushing tubes where all darn close to centered now, maybe just a tad offset to the outside. Not sure if 6 controls arms is a representative sample..... A testament to the dominant direction of travel and forces applied differently? 

    C2DDDE92-7324-4B25-A484-BE7B91B696EA.jpeg

    E74B8624-6ED1-4273-BF13-B9D0A1D71237.jpeg

    One set of new bushings I have laying around has the offset center tubes. No clue as to vintage. I have a set to install today, I’ll use the advice and experience detailed above. Thank you.

     

    Edited by zKars
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    Ahhhh, Jim's emporium. I will have to make a pilgrimage one day....

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