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Thread: B13 rear suspension re-assembly problem. Alignment all wrong. (Broadband only!)

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Posts: 51-60 of 97
2008-07-24 17:43:15
You should read this entire article:



2008-07-25 02:56:11
As soon as you post those pics we will be able to tell exactly what went wrong. Get on it!
2008-07-26 01:35:52
Originally Posted by BenFenner
You should read this entire article:



Gigant damn pics go here!!!

thanx Ben that's usefull!!!
2008-07-26 01:52:21
Get that giant picture quote monstrosity out of my thread. =P
2008-07-26 03:02:24
Originally Posted by BenFenner
Get that giant picture quote monstrosity out of my thread. =P

done mister! jaja only cos you're my hero
2008-08-08 13:57:12
I got the parts in today (Thanks Greg V.). I promise updates and tons more pics in the near future.
2008-08-11 17:08:13
I'm recovering from a Sunday under the car. Long story short: I'm not much better off than when I first fυcked the car up.

Yah so, that was an almost complete waste of time and money. I say almost because a few things are better, but it's not due to anything I couldn't have done with the ES bushings. There's been no other time when I was so frustrated with anything. I'm used to things following the laws of physics and logic. My car seems to defy both, which is really getting to me now.

I took a bunch of pictures before disassembling, nothing of note to see really. Forward parallel link is upside down because the last time I put it back together I tried a trick passed on by Greg V. from someone else. Greg heard that it helped with binding. From a geometric perspective there is no difference between the link being right side up or upside down as the distance between the mounting holes is the same. Unless they were talking about interference with a sway bar, there's no difference. The only thing flipping the link upside down did was massively interfere with my progress swaybar, which explains why it's not in these pictures.

The rear end is in the air now.

You can see decently well the toe in here. This is the really bad side. Sorry I couldn't get a good angle to show it. I didn't think of a good angle until later.

Next are pictures of the new parts with part numbers and stampings and color coded dots and such. The definitive information on there real parallel links is as follows:

Front (towards front of car):
Part #: 55121-50Y10
Color of dot: White
Numbers stamped into the metal: C45H or similar
Other: Tiny hole by bushing is larger than the rears, and is a more well formed circle
Length: Continue reading on to next post

Rear (towards rear of car):
Part #: 55121-50Y00
Color of dot: Yellow
Numbers stamped into the metal: S82H or S84K or similar
Other: Tiny hole by bushing is smaller than the fronts, and is a less well formed circle
Length: Continue reading on to next post

Putting both bolts through to show how little difference there is in the length of the parallel links. Fronts are on top and are minimally longer. Sliding the second bolt on the left took little effort as it slid right in (that's what she says).

Switching things up and organizing the links in a different order than before. It goes front, rear, front, rear. Sliding the second bolt on the left surprisingly took a bit of effort, minor bending and overall saw much more resistance as it was pushed in forcefully (t__t's w__t s_e s__ys).

Rear parallel link #1, right hole.

Rear parallel link #2, right hole.

Front parallel link #1, right hole.

Front parallel link #2, right hole.

Rear parallel link #1, left hole.

Rear parallel link #2, left hole.

Front parallel link #1, left hole.

Front parallel link #2, left hole.

Image limit reached. Continued in next post.
2008-08-12 16:09:00

At first I thought there was absolutely no way to tell the front parallel links from the rear but I was wrong. The OEM parts come with a white dot on the fronts and a yellow dot on the rear. In addition to this they have codes stamped into them (see pictures). My parallel links were lacking these stamps making me think they were aftermarket. Also the tiny hole towards the bushing is larger and more well formed on one set of links (see pictures). I measured carefully and ended up with these measurements from one end of the metal sleeve in the center of the bushing to the other opposite end:

Front link #1: 15 15/32 inches 392.90625mm
Front link #2: 15 14/32 inches 392.11250mm
Rear link #1: 15 14/32 inches 392.11250mm
Rear link #2: 15 13/32 inches 391.31875mm

You tell me 1.6mm difference between the longest and the shortest parallel link is significant when the toe adjustment bolts allow for aprox. 10mm total adjustment. Not to mention my measuring technique isn't accurate to smaller than 1mm if that. These are the same damn parts. At one point they may have been different, one having abs bracket holes and one not but if you were saving money at Nissan and the parts were so similar, wouldn't you just make one god damn part? I think they just haven't gotten around to merging the part numbers.

I took everything apart (okay to be fair Dan took everything apart while I took over 9,000 pictures of the new parts) and took some pictures of the bent bolts.

To be honest, one bolt was bent much more back when I re-installed them to take a 2,000 mile trip. Now they were both bent about the same, but they were both bent less than before. I have an explanation for this. When I put it back together that time I made sure to orient the bend opposite from how it wanted to sit. Provided the bolts never spun, they bent straight and then proceeded to bend more but not as much as before. This is due to torquing the nuts less. See the explanation below of the bending bolt to see why this matters. The bend seems to be 2/3rds of the way down each bolt (again, see explanation below) and here are the pictures proving they are bent:

New bolt against straight edge. Bolt is straight.

Old bolt against straight edge. Bolt is bent.

Old bolt up against new bolt. Bend leaves gap between them.

Showing that one end was pressed together.

Showing that the other end was pressed together.

This is what two straight bolts look like together.

Old bolt sandwiched between two new bolts. Bend is obvious.

Old bolt has been rotated to make the bend face towards the ground. Old bolt looks straight but is not.

Two old bolts together showing the combination of the bends. Giant gap is due to the bolts being bent.

Showing one side is pressed together.

Showing the other side is pressed together. You can see the bend clearly even here.

Dan and I put everything back together and crossed our fingers. We ran into another unforeseen problem and further proof something was terribly wrong. Here's assembly pictures:

New problem. The straight metal slats are used to position the toe adjustment bolt in the elongated hole. If these aren't straight, they won't do their job very well. The side that's been worse all along had a good bend in one of the slats. The up and down motion combined with the bent bolt caused this lateral stress I believe.

After some attempts at fixing it.

Here is the passenger's side.

After completely fixing the bent section.

Not great but it will have to do. I clamped some vise grips on it and bent it back into place. Seemed to work the best of all the techniques I tried.

We dropped the car down and the alignment was the same as before. We rolled it forward and back took some pictures. I'm sorry I didn't take good pictures like this before disassembling but I didn't consider the angle until now. The alignment hadn't gotten any better. It was the same. Terrible toe in and driver's side wheel inboard more so than the passenger's side. The negative camber may have been a bit better, but probably not. This is how bad it's been the whole time:

Rear driver's side.

Rear passenger's side.

Rear driver's side again.

Rear passenger's side again.

We decided to let our brains rest and drop the struts to make sure the hats and spring tops were indexed properly and found they were as they should be. Arrow on spring hat pointing outboard, L and R correctly oriented (L to driver's side and R to passenger's side):

Image limit reached. Continued in next post.
2008-08-12 16:10:47
Next I loosened every mounting point on the major offender's side (driver's side) and checked the play in every mounting point, put the suspension through it's motions and just generally thought about the problem. I noticed that even now the long bolts looked bent. I was pretty sure that wasn't the case, and it must have been an optical illusion by how cοck-eyed the parallel arm was compared to the bushing and the bolt. I found what I believe is the source of the bent bolts. First off, when pushing the long bolt first through the front parallel link, then through the first hole in the cast iron knuckle the bolt heads straight through to the second hole in the knuckle but misses the center of the hole completely. I know this isn't scientific, but it seems that the holes in the knuckle once were aligned and now they are off some. This however isn't the biggest problem. The bolt can be coerced into the second hole without too much difficulty and then it passes through the rear parallel link. This is where the major problem lays I believe. The rear mounting hole in the knuckle is not flush. What I mean when I say this is that as the bolt enters the hole it crosses the first plane which is flush with (parallel to) the two planes of the first hole. As you exit the rear hole with the bolt the plane you just broke is not flush with (parallel to) the other three planes. It looks like this:

Both knuckles had this abnormality. From an engineering point of view this makes no sense at all and I'm attributing it either to casting imperfection and poor quality control on Nissan's part or there's a tiny possibility that when I took the cutting wheel to the car the first time to get everything apart I managed to cut into the cast iron at this less than ideal angle. Either way, when the nut on this long bolt is tightened down the metal center of the bushing ends up mating up with this stupid angled plane and if the rubber isn't flexible enough, enough force could be applied to the bolt itself to bend it. It doesn't help that the first time I assembled everything I torqued all the 22mm nuts/bolts to 80 ft. lbs. or more. This is way above the 55-65 ft. lbs. in the FSM. It wouldn't normally be a problem to torque that tight but in my case it made things worse as it pressed the metal sleeve in the bushing up against the plane of the knuckle with enough force to compress the gap completely:

This shows what happens when you tighten the nut down any considerable amount:

This is a bit exaggerated, but you get the point. The reason the parallel link doesn't completely match what the bent bolt does is because the bushing allows for some play. ES bushings in this situation were a lot worse. Here are pictures of the real thing:

If this were the case the entire time with my car, the correct torque on the nuts and the flexibility of the rubber could have made all the difference. You will notice that this also forces the rear portion of the knuckle outboard some, which exacerbates the toe-in problem I have. After looking at the cast iron surface carefully and determining that I hadn't caused this situation with the cutting wheel (sorry no pictures, I was frustrated and filthy at this point) I decided to correct what I felt was an engineering error and/or oversight by Nissan. I took the cutting/grinding wheel to the cast iron knuckle and fixed that bastard (sorry no pictures, I was super frustrated and super filthy).

I know this was a ballsy move that not many would have attempted but I'll be damned if I couldn't make a better rear suspension than the sad fools who cut corners on our cars.

Cutting down the cast iron knuckle helped to orient the link with the bolt properly whose misalignment I believe accounts for the bending bolts, and removes the possibility that it will ever happen again, ES bushings or not. The parallel link was not perpendicular with the bolt yet even after all this, as at full droop the suspension still looks like this:

After doing this and getting every ounce of toe-out I could from the entire assembly and then tightening everything up to keep the toe-out I dropped the car again and gave the alignment a good look. Nothing had changed and I was no better off than before. It was late, my back was killing me, I was terribly frustrated, dehydrated, hungry, my head was spinning, I was dirty and sweaty, I had work early the next morning and this weekend wasn't the relaxation I needed from the previous week. I decided to give up and see what I might come up with after a night's sleep. Before cleaning up for the night I put the rear toe adjustment bolts at their most extreme toe-out setting (way past the adjustment marks on the washers) and never took any pictures because, well, I was not up for it. I'll maybe get pictures of the final alignment soon.

This was familiar territory, as this was the situation I drove off with the first time I put the ES bushings in. The toe adjustment bolts were at their extreme and things looked sort of okay. The passenger's side had almost neutral toe or maybe a tad bit of toe in, camber was a tad on the negative side and the tire mated up well with the fender being flush as it used to be. All in all the passenger side is livable.
The driver's side is suffering from a tiny bit too much toe-in, a tiny bit too much camber and the tire ends up being a tad bit inboard all together. You've just read a novel (this entire thread) on how to spend a bunch of money and countless hours just to end up worse off than when you started. I can think of a couple things I'd rather have done with that time/money, couldn't you?

The only consolation I feel is that I now know everything there is to know about the B13 rear suspension and there's this thread to shed more light on its mystical workings.

Before all of this started I had incredible rear tire wear characteristics. After the second installation of the parallel links (1 week after the first in hopes of fixing the problem in preparation of a road trip) and the 2,000 mile road trip I'd reduced my brand new rear Falken AZENIS RT-615 tires to treadless carcasses. The fronts on the other hand are wearing extremely well. With this final installation and adjustment I'm confident that my tire wear will improve quite a bit (should have left it this way before the road trip but I was stubborn) so all was not lost. I could have gotten this out of the ES bushings though, and something is still very wrong as the maximum adjustment is needed to even approach a good alignment. Before all of this started the toe adjustment bolts were almost at the middle of their adjustment.

It seems almost as if the rear-most mounting points on the chassis have shifted outward and/or the forward mounting points have shifted inward. Either that or the old parallel links grew and shrank respectively when I took them out and the new ones from Greg are just as fυcked. I just can't seem to get stock components to give me a stock alignment. The only non-stock pieces are the springs and struts, but I had a perfectly fine alignment after installing them and riding with them for a while so I've ruled them out. There's a small possibility I could sort of help the situation by finding the longest and shortest links and using that to my advantage but that wouldn't get me nearly back to where I was when things were perfect. I know this is a stretch (and I hope it's a stretch) but here's some pictures of the parallel link mounting points on my car:

The side that the metal seems to have separated from the frame rail is the side that's causing the most problems, but the other side has massive issues as well and doesn't look nearly as bad. I don't think this happened recently, I think the car came like this from the factory. Still, the idea of putting the car in a frame straightener of sorts has crossed my mind.

Last night I decided to put this project on the back burner as the alignment is halfway decent and the bolts shouldn't bend. After sleeping on it, I'm thinking the real/correct answer is to move the mounting points of the parallel links on the chassis around with some cutting and welding. This should get everything back to normal. Modified parallel links would get the job done too but is the less elegant solution. Either stock units could be cut and welded to be shorter/longer or once again something like the Ingalls Engineering's adjustable parallel links could be used. The GA16 powered cars share a parallel link part number with the SE-R and the other link is a different part number altogether. Maybe the part from the non SE-R chassis is the answer...
2008-08-12 17:29:17

Comments? Concerns? Suggestions? Questions? Praise? Beratement? I'm game.
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