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Old 07-19-2016, 01:12 PM   #21
Reserector
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A spherical bearing could be installed (pressed) into a sleeve that has been welded into the frame. The sleeve could have internal grooves for retaining rings.

The down side would be that any impact from potholes would not be absorbed as it would be by a compressible bushing. I think it would be great on the track, but not so much on the street.
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Old 07-19-2016, 01:18 PM   #22
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Originally Posted by Reserector View Post
A spherical bearing could be installed (pressed) into a sleeve that has been welded into the frame. The sleeve could have internal grooves for retaining rings.

The down side would be that any impact from potholes would not be absorbed as it would be by a compressible bushing. I think it would be great on the track, but not so much on the street.
Good idea about having grooves cut in a retaining collar.

The way I was describing it, the bushings would still be used and impact from potholes would be absorbed. The rod would not be "fixed" to the spherical bearing, but be free to move in it back and forth as much as the bushings allow. Of course, you would need a bit of grease on the rod to reduce the metal-to-metal friction.
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Old 07-19-2016, 03:17 PM   #23
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gotta remember which parts carry the load when the load is axial or radial to the tension rod. the tension rod puts all the force on the forward bushing under an axial load that runs front to back and on the rear bushing int he opposite. I THINK under a radial load the cup lips take all the load. thus the spherical bearing would just be a pivoit
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Old 07-19-2016, 04:43 PM   #24
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gotta remember which parts carry the load when the load is axial or radial to the tension rod. the tension rod puts all the force on the forward bushing under an axial load that runs front to back and on the rear bushing int he opposite. I THINK under a radial load the cup lips take all the load. thus the spherical bearing would just be a pivot
Exactly.

Except that in my case, an upward "radial" force on the rod, caused by twist on the control arm, overwhelmed the compressive force by tightening the nut, keeping the OEM bushings in the OEM Nissan cup holders, even when the bushings were fully compressed.

Once the bushing leaves the cup, the radial load is then carried by the sleeve, and when that gets sawed through, the rod itself.

In other words, if you take off my bushings and sleeve, just leave the rods in, the rods will not rest peaceably in the center of the bracket holes. They pull upwards and will contact the top of the bracket holes!

A tight fitting, poly bushing, well-compressed into a deep cup, like an outer bearing race, will keep the rod and sleeve centered in the hole. If the poly eventually ovals, the sleeve will start sawing the bracket hole once again.

On the other hand, if a spherical bearing is in the bracket, the rod is going to be held in the center of the bracket hole, no matter what, even if you did not have bushings.

The spherical bearing would act as a pivot, but also will counteract any radial forces caused by the control arm. Maybe not everyone's control arm wants to twist like this, but this truck is like that, and I will add, all the suspension bushings are OEM and new, plus, the torsion rods are within the spec range.

What is odd about this idea of using a spherical bearing is that the rod would have to move in-and-out of the id of the bearing. That is not a normal situation for a spherical bearing, but since the movement would be constrained by the bushings, and since the bushings would shield the rod from the elements fairly well, it seems that with a little grease on the rod it would work well for a long time.

Last edited by chickenfriend; 07-19-2016 at 05:34 PM.
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Old 07-19-2016, 05:23 PM   #25
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Keep in mind that when 4wd is engaged, the rid is in tension, which applies a compressive load to the REAR bushing.
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Old 09-15-2017, 08:27 PM   #26
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Quote:
Originally Posted by chickenfriend View Post
I read Fords have quite a bit of trouble with their compression rods, which they call "radius rods". Apparently, their brace bracket is replaceable, held on the frame with two rivets.

I have noticed a definite tendency of the Nissan compression rod to push upward when the truck is as rest, pushing the bushings upward and over the edge. Sometimes they re-seat themselves.

Picture of bushing being pulled up out of the stock Nissan cup with stock bushings by upward force exerted on compression rod by angle of control arm:


Short term results:


Some more measurements may be of future interest:
Nissan OE spacer sleeve ID: 17mm, OD: 22mm, 60.0mm length and the part number is 54479-50WOA Collar Tension Rod, for one sleeve.

OEM stock sleeve has a wall thickness of 2.4 mm with a welded seam.
Two aftermarket sleeves I measured were 10mm longer than stock Nissan; I don't know why they make them different, but I plan on using Nissan sleeves. The length of the Nissan sleeves is exactly the same as the threaded part of the rod.
The unthreaded portion of the Nissan compression rod, where the sleeve slips over, is 16.0mm in diameter.

I put grease between the sleeve and the rod.

The Nissan cup inner diameter is 27.0 mm, that is the hole in the middle. However, the Nissan cup hole is dished with a small lip that fits into and self-centers the cups in the frame hole, so the outer diameter of the lip is closer to 30mm, which is the diameter of the hole in the frame bracket.

When the rod with the sleeve is centered in the bracket hole, where should be an air gap of 2.5mm all the way around the sleeve (27mm - 22mm = 5mm of diameter).

I am looking at this problem ONCE again, as I was preparing to remove the Nissan cups I welded in last year, and replace them with outer bearing races, LM67010.

Do NOT make this repair with the Nissan bushing cups! They will NOT hold the bushings centered, and will rust out just as fast as the original ones. You will waste your time as you cut off your old welds then try to smooth the area back out again for outer bearing races.

The truck is fully weighted on all four wheels. After removing the two front bolts holding the compression rod, I noticed that the bar sits perfectly centered over the holes, with the bushing nut on the other end on fully. That's good.

However, with the rod still held by the compression nut, and allowed to center itself naturally by the bushings, there is a gap of 1/2" between the top of the bar and the control arm.




Not only are the bolt holes still aligned, but the face of the bar parallels the control arm nearly perfectly. So, why the gap?
Another angle. The compression rod is in a neutral, resting postion, bushings fully compressed to the sleeve spacer:







Now, when the rod is drawn up to the control arm like that, the control arm pulls the rod upward at the bushings, too. This pulls the bushings out of the top of the cup, and deforms them due to the constant stress when the truck is sitting...................
Can't see the images
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Old 09-15-2017, 08:39 PM   #27
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Quote:
Originally Posted by Jonny88 View Post
Can't see the images
That is because of the Photobucket catastrophe this year. They want 400$ per year to host hotlinked images. You can Google it.

I read somewhere they will show up with a particular browser, some sort of work-around.

Other than that, I would need to sit on my butt for a week and load the pics into a different host which would need to be free and allow hotlinked images.
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Old 09-16-2017, 12:25 PM   #28
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sometimes i use http://tinypic.com/
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Old 09-16-2017, 06:46 PM   #29
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Old 08-05-2018, 04:16 AM   #30
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Thanks a bunch for your detailed thread on this. I was in a pinch recently when I realized how badly damaged my recently acquired 720 was. I bought the truck with nearly 290,000 miles and threw a few grand at it to replace tires, axles, brakes, and exhaust. I knew I would need to do some work, but when I took it in to get it aligned I was told I would need to take it to a full service frame shop to get it welded because the strut brackets were so badly worn and "egged." The only body shop I took it to said they couldn't work on it, and that I would need to find a way to correct it myself. I did a little homework, stumbled across a YouTube video that mentioned something about bearing races being as cups, did a few searches, and stumbled across this thread. It seemed like a great solution, but I've never welded anything in my life. So I read it dozens of times, sourced the parts locally, and found a welding pro on Craigslist who did the job for cheap. I had a hell of a time getting one of the two strut rods lined up because something was just slightly cattywampus, but after much cursing and some scraped knuckles, leg power was applied and the bolt was seated with a resounding crack of the mallet. The nuts were tightened and the truck was taken for a victory run. It drove straighter than ever.

As I'm a novice wrench, this project required several hours of labor, and probably just under a hundred bucks. For anyone else in this predicament, this is an excellent solution to your problem, especially if you know what you're doing and have any welding ability. Also, you can probably find bearing and screw retailers in your area that will have these parts, and then you won't have to roll the dice ordering them online. The LM67010 is a universal part number. Just make a few calls and see if you can pick one up. I'm going to post a few of the pictures I took. Please feel free to message me if you have any questions.

Again, thanks for posting this. You really saved my bacon. I don't know how I would have figured this out otherwise. https://photos.app.goo.gl/3spvLemwovRC2xU88
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