Rear control arm bush alignment

[ToolBoy]

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 

[grannyknot]

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.

[Captain Obvious]

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:

 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.

[ToolBoy]

        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"  

[Captain Obvious]

Glad to help and if there's any issues with the bushings come install time, just post 'em up!  

[ToolBoy]

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

[ToolBoy]

Thanks to grannyknot too. . . 

[Captain Obvious]

Excellent. Glad to hear they went in without incident.      

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

[ToolBoy]

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

[Captain Obvious]

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.     

 

[ToolBoy]

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".

[Captain Obvious]

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.