Go Back   Infamous Nissan - Hardbody / Frontier Forums > Model Specific > Hardbody Forum (D21)

Reply
 
Thread Tools Display Modes
Old 07-11-2016, 01:03 AM   #1
chickenfriend
 
Join Date: Aug 2013
Location: Virginia
Posts: 229
Vehicle: D21 1987 VG30 v6 SE King Cab 5sp Manual 4WD FS5R30A 5-spd trans
Thanks: 4
Thanked 18 Times in 13 Posts
Default Nissan D21 Hardbody Tension Rod Compression Rod Strut Rod repair

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.

After welding on new Nissan bushing cups last year and using aftermarket bushings and then going back to stock bushings, I noticed that no matter what, the dang bushings wanted to ride out of the top of the cup. That makes the inner metal sleeve rub on the hole, "egging" it out.

Once the hole cuts through the sleeve, the rod is next.

All these problems are compounded by the fact that this entire area is very rust prone.
Bearing cups are going to hold those dang bushings in place, but even when the truck is at rest, the bushing are going feel pain, especially the soft OE Nissan bushings.

Even with the bearing races welding in for cups, it still seems possible that the OE bushings could deform enough over time to allow the spacer sleeve to start being hacksawed by the frame hole.

The aftermarket bushings are much harder and it seems that if their more-or-less blunt or flat end is placed first into the bearing race cups,
that there is a good, snug fit. Put the bushing in with the cone side first, and there is quite a bit of play. This is going to let that sleeve start rubbing the frame.

So, we can put the cone outward facing, and turn the disk washers around to cup the cone a little.
I will probably use the aftermarket bushings with the OE sleeve. When fully compressed, I want my two two bolts line-up with the control arm. I don't want the rod to be pushed forward.

It has become obvious to me that this suspension design asked this rod and bushing cluster to do too much.

That rod is getting twisted and torqued by movement of the control arm up and down, and it is getting twisted by the torsion rod, via the control arm.

The best we can do with this seems to be to confine the bushings to the cups as much as possible to keep the spacer centered in the frame bracket hole, then live with it.

Instead of having a heavy duty rubber bushing in the rear of the lower control arm to match the front of the control arm, to provide good control, two deformable rubber bushings in too-shallow holding cups were asked to do the same thing. The design wasn't up to it.
Large stainless steel backing washer centers in chamfer on bearing race backside.

Welded in just like that.



I did file out the center of the washer some with a half-moon file. The Nissan cups have a 28mm hole, so I opened the washer holes to about 29mm. If the sleeve rubs it, I'll just open it up some more with a file.

Used a 1" diameter bolt and a few washers/bushings to hold the bearing race and backing washer in place for tack welding. Other times, I used a clamp.

Welds are sloppy because of AC stick. Mig is preferred, if available. I will take out the bolt after tacking, and put a few spot welds around it, then I will paint it. I'll leave the bottom unwelded so water won't get trapped behind it.



Front bearing race and backing washer installation finished:




Before welding, I completely disconnected the battery and unplugged all wires in the under-seat computer.

Prefererred orientation of aftermarket bushing. Flat end goes into the race, not the cone end:



Interesting to find out that the torsion bars will touch the compression rod bracket when wheels are on full lock:



Aftermarket bushings FA7158 did not allow enough compression to center holes for the two arm bolts, so I removed 1/2 cm from each bush of the pair. That reduced the overall length of the two stacked together to the same length as the stock Nissan sleeve.

Basically, how much to remove was an educated guess. I noticed the aftermarket sleeve was exactly the length of the two aftermarket bushings stacked together, so I cut enough off the bushings to make them the same length as the stock Nissan sleeve which I was going to use, instead.

This was about half of the cone taper as seen on the bushings.

Pic of shavings from bushings:




C-clamp helps bring the control arm together with the rod to get the bolts in;



Turns out, this was about the right amount to remove. When I tighted the compression nut fully (when it runs up against the sleeve), I was able to get the bolts in without too much hassle.

Picture of the completed job, using second "jam" nut to lock the first:




The dished washers are "concave out" like there are with Nissan stock. When I had them around the other way, it looked like the lip of the washer might start cutting into the bushing.

If you re-use your old locknut, you may find that it will unscrew itself. The solution is to snuggly jam another M16 x1.5 nut on top of the nylon nut and add Loctite to the nut threads.

+++++++++++
Alternative #2? Spherical Bearing Idea:

The only other way to fix this is with a plain spherical bearing. The racing stores sell weldable collars that can be used to hold the bearings.
In this application, you might be able to get something in the 30mm frame hole if the bore of the bearing is to match the rod, which is 16.0mm diameter. If the the bore were to allow the sleeve, too, you would have to have a bigger bearing and might have to hog-out the hole.

If I were going to try that, I would probably opt for a 16 mm bore bearing, and cut the sleeve into two lengths.

One possible problem is that the two sleeves would need to be short enough so that the rod is free to move a little back and forth in the bearings.

Otherwise, the rod would be locked-in against the bearing if the sleeves were butting it on each side, making the bushings pointless regarding their shock absorbing trait.

One huge benefit of a spherical bearing would be that the sideways pressure on the poly/rubber bushings is gone, since it would maintain the rod in a central position. The rod would still be able to move back and forth, so you would want a little grease on it to keep that smooth.

Last edited by chickenfriend; 02-11-2018 at 06:39 AM.
chickenfriend is offline   Reply With Quote
Thanked by:
waynedef (08-05-2018)
Old 07-11-2016, 01:07 AM   #2
chickenfriend
 
Join Date: Aug 2013
Location: Virginia
Posts: 229
Vehicle: D21 1987 VG30 v6 SE King Cab 5sp Manual 4WD FS5R30A 5-spd trans
Thanks: 4
Thanked 18 Times in 13 Posts
Default

Interjection update, several years later:

About the gap I show and talk about, above, I now wonder if it is caused by not having the torsion on the control arms set to spec. If you have the gap like I did, I would first check the torsion spec for your model of truck and making sure the source for your spec (Nissan Service Manual being the ultimate source) is correct.

I had to adjust the torsion bars last year after having to remove the torsion bars for a clutch job. I think I have a plausible theory that incorrect torsion on the bars could cause the gap.

This leads to the possibility that my "cutting" seen on the strut collar could be caused, or made worse, by the torsion bars and control arm set incorrectly.

So, definitely check the torsion bar-control arm spec (ride height) as part of the repair procedure.

Last edited by chickenfriend; 09-25-2019 at 10:08 AM.
chickenfriend is offline   Reply With Quote
Thanked by:
alabama_lowlife (07-11-2016), jp2code (07-11-2016)
Old 07-18-2016, 03:44 PM   #3
street_rulerr
 
Join Date: Nov 2015
Location: West Coast
Posts: 2,266
Vehicle: 1996 4x4 5spd
Thanks: 0
Thanked 201 Times in 190 Posts
Default

so with all this being said, its the CUPS that are supposed to carry the up and down load of the bushing. and when the lower A arm cycles up and down, it pulls the bushing out of the cup allowing it to ride one way or another correct?

In the first picture it looks like your cups are completely missing. If you HAD cups still, i assume that if you can cycle the a-arm and reef down on the bolt tight enough while having the a arm in different positions, you could take out all of the fore-aft motion of the rod and really load up the bushings to keep them from walking out of the cup.
street_rulerr is offline   Reply With Quote
Old 07-18-2016, 03:46 PM   #4
Reserector
the Flaming Marshmallow
 
Reserector's Avatar
 
Join Date: Oct 2015
Location: Laurel, MS
Posts: 1,579
Vehicle: Nissan HB KC 4x4
Thanks: 26
Thanked 381 Times in 302 Posts
Default

Yes, the cups do the centering. I wouldn't say that it should ride out of the cup. It should distort, is all.
Reserector is offline   Reply With Quote
Old 07-18-2016, 03:51 PM   #5
street_rulerr
 
Join Date: Nov 2015
Location: West Coast
Posts: 2,266
Vehicle: 1996 4x4 5spd
Thanks: 0
Thanked 201 Times in 190 Posts
Default

also do you have the nissan cup part number? i need one as an example
street_rulerr is offline   Reply With Quote
Old 07-18-2016, 03:57 PM   #6
chickenfriend
 
Join Date: Aug 2013
Location: Virginia
Posts: 229
Vehicle: D21 1987 VG30 v6 SE King Cab 5sp Manual 4WD FS5R30A 5-spd trans
Thanks: 4
Thanked 18 Times in 13 Posts
Default

Quote:
Originally Posted by street_rulerr View Post
In the first picture it looks like your cups are completely missing. If you HAD cups still, i assume that if you can cycle the a-arm and reef down on the bolt tight enough while having the a arm in different positions, you could take out all of the fore-aft motion of the rod and really load up the bushings to keep them from walking out of the cup.
No, the cups are there in the first picture, as I indicated above that picture. They were NEW Genuine Nissan cups! If I had not painted them black, they would be easier to see.

In fact, since it appears to you that the cups are missing proves my point: there is not enough there to retain the bushing. That's why the outer bearing races are necessary.

You can tighten the rod nut all the way down,but the bushing will still jump the Genuine Nissan cup if there is any off-centered force on the rod.

Once the bushing is out of the cup, then begins the hacksawing process of the bushing sleeve against the frame of the truck.

First, the sleeve gets sawed, then the rod is next. I remember a forum post where the rod broke in two. Mine was sawed on, probably 20% of the diameter. I don't like to take chances so I replaced the rod. They are still available from Nissan.

More than that, the hole in the support bracket gets ovaled by the rubbing of the sleeve against it.

There are probably other aftermarket bushings out there, so you may need to modify them or not modify them, differently than I have done with the particular aftermarket brand I used.

To repeat, I did use the aftermarket bushings, but with genuine Nissan "sleeves" and the part number for the Nissan sleeves is included in my leading post above.

Last edited by chickenfriend; 02-22-2019 at 02:55 PM.
chickenfriend is offline   Reply With Quote
Old 07-18-2016, 04:00 PM   #7
ahardb0dy
The Post Count Whore
 
ahardb0dy's Avatar
 
Join Date: May 2014
Location: Sorrento, Florida
Age: 55
Posts: 7,701
Vehicle: 2017 Nissan Frontier Desert Runner
Thanks: 67
Thanked 949 Times in 869 Posts
Default

Part Number 54478F0200
Part Name WASHER
MSRP $9.75
Core $0.00
Online Price $6.57
__________________
My name is Tony and I'm a Infamousaholic

Current truck - 2017 Nissan Frontier Desert Runner ,

(formerly owned: 1993 Nissan Hardbody king cab 2wd, 90 Nissan Sentra, 94 Nissan Pathfinder SE 4x4, 05 Nissan Titan, 87 Nissan SE-V6 4x4 king cab, 94 Infiniti Q45t & 80 Datsun 310GX )
ahardb0dy is offline   Reply With Quote
Old 07-18-2016, 04:01 PM   #8
chickenfriend
 
Join Date: Aug 2013
Location: Virginia
Posts: 229
Vehicle: D21 1987 VG30 v6 SE King Cab 5sp Manual 4WD FS5R30A 5-spd trans
Thanks: 4
Thanked 18 Times in 13 Posts
Default

Quote:
Originally Posted by street_rulerr View Post
also do you have the nissan cup part number? i need one as an example
Example for what?
chickenfriend is offline   Reply With Quote
Old 07-18-2016, 05:50 PM   #9
street_rulerr
 
Join Date: Nov 2015
Location: West Coast
Posts: 2,266
Vehicle: 1996 4x4 5spd
Thanks: 0
Thanked 201 Times in 190 Posts
Default

I want the cup for measurements. I like to have things in front of me.

so heres my plan since welding isnt an option for me. Im going to admit that my brother in law is a professional welder, but i just really dont want to go that route right now.

I happen to be taking a machining class for a mechanical engineering degree im in the middle of and have access to a full NC machine shop.

My plan is to round out the existing hole in the frame and machine a new sleeve that will slip over the existing bushing sleeve and sit between the bushings. This is what the tension rod and frame will ride on. This should take up the space thats been "egged out". However this doesnt sound like it will fix the issue of the bushing walking around.

I looked at the torque spec on the big 24mm nut and it looks to be something over 100ftlbs. I cant remember off hand right now. but it was a lot. and it really signaled to me that the preload on the tension rod, putting the rod in tension (this is how bolts actually work from an engineering perspective) was meant to keep the bushing in place and less the cup. basically im going to torque the shit out of the bolt while cycling the a-arm through its full arc. raise a-arm, torque, raise a little more, torque repeat till comfortable.

Additionally, all of the bolts on the tension rod are designed to yield. If you look really closely you can see the "top" of the nuts are actually conical. This is to yield the last few threads to "lock" the nuts into place. I need to get new ones so i can accurately torque the large 24mm nut. Right now i think about half the force i put on the bolt is being eaten up by the friction of those threads having been yielded and me trying to put it back on.

this is all theoretical and may not work for shit in the end but its the initial route i want to go as opposed to welding. however if i have to weld, i will weld on a "sleeve" around the existing cup thats machined out to slip over the cup and weld to the frame. it will have this weird stepped shoulder inside of it to fit over the cup and then house the bushings
street_rulerr is offline   Reply With Quote
Old 07-18-2016, 06:17 PM   #10
chickenfriend
 
Join Date: Aug 2013
Location: Virginia
Posts: 229
Vehicle: D21 1987 VG30 v6 SE King Cab 5sp Manual 4WD FS5R30A 5-spd trans
Thanks: 4
Thanked 18 Times in 13 Posts
Default

The limit of the torque on the large nut is determined by the loose sleeve which fits over the rod.

In other words, once the nut reaches the sleeve, it stops. Tighten it too much and the sleeve will buckle, especially if it is one of the cheap aftermarket sleeves.

As I noted, the twisting motion of the rod can "unscrew" the nut, even if it is a nylon locknut.

You can use non-nylon locknuts, but they could be hard to find in metric, at least a small quantity. Lockwashers will not work.

I recommend two nuts with locktite on the threads; the outer nut being the "jam" nut. Added benefit of the thread sealer is that the threads are protected from the elements, making it easier to remove the nuts at a future time, like when the bushings need to be replaced again.

If you are taking a machining class, you will or should at some point be taught welding. Many machinist are excellent welders because they need to be.

If you machine out a bushing sleeve "to slip over the existing bushing sleeve", your poly or rubber bushings may then have too small an inner diameter to slip over your second sleeve.

Last edited by chickenfriend; 02-22-2019 at 02:56 PM.
chickenfriend is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 02:03 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.