Is it appropriate to adjust control arms to prevent track bar from hitting differential?

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Fargo

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In my willingness to 'take one for the team', I purchased a track bar that was not on the approved list for 2" lift. (I won't state the brand name at this time because their tech department is currently working with me.) I took the chance on this track bar because it was being sold as fitting lifts from 2"-5" and it checked off all the right boxes for me. (It had a DDB bushing, and maintained all factory mounting systems) This track bar was also a new design and to my knowledge hadn't been tested for fit by anyone on the forums. But like so many other track bars, it appears its going to have issues with diff covers.

With my control arms all set to factory lengths, it is clear the track bar hits the diff. In fact I estimate I would need 4" of bumpstop to clear the Dana 44. However, I have not set castor yet and it is currently sitting a 5 degrees. I believe factory recommends 7 degrees. Since I have adjustable control arms, I could tip the differential back a little to get the castor back to 7 degrees. But I doubt that will be enough to eliminate the problem.

So onto my questions.
  1. When people say that track bars like Currie, JKS, and Metal Cloak fit. Are they using stock length control arms or have they adjusted the arms to fit the track bar? I want to be fair in testing this track bar against other options.
  2. What is the appropriate way to setup my suspension. What should my castor be set at to avoid excessive driveline angles (at 2"-3" lift) but still provide on center feel. (5 degrees feels ok to me) Should I shorten all my control arms in an effort to make the track bar fit? This seems wrong to me. If the problem is the track bar, then I need a new track bar. I don't want to sacrifice driveline angles and cause other issues by messing with the control arms to fix a track bar issue.
Thanks for the help.
 
You may only need a track bar relocation bracket , in whatever brand you are ashamed to admit you bought .

And for the record , I have a Rough Country lift (sort of) and a dropped pitman arm (and mount ) , so I'm not politically correct ...but I fixed the weaknesses and am very happy with where I am for now.

There are some great brands recommended here , but some of the ones that aren't so great can be remedied to good performance.
 
For question #2 : I don't think anyone can tell you really what your castor angle should be for your setup. The driveshaft angles take precedent over actual castor measurements. So start with angles and castor largely is what it is. Aim for zero difference between the driveshaft and pinion yoke and the castor should feel ok. For what it's worth, I run 35's with equal angles and it turns out to be just about 5 degrees castor with good road manners and steering return. Larger tires can get away with less castor. If you aim for 7 degrees castor with a suspension lift, your pinion yoke is going to be way low and you'll almost certainly have vibes.

For question #1 : When you say the track bar will hit the diff cover - does that mean rubbing contact or snap in half contact? Stock diff cover I assume?
 
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Adjust the arms to get what you need to make the track bar clear. That is what adjustable arms are for. If you can't get that, then your track bar sounds like a problem.
 
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I used a JKS trackbar with my factory control arms at 2" of lift. Cleared the differential fine (Dana 44). This is at full bump.
20180204_151119.jpg
 
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Mike_H said:
I used a JKS trackbar with my factory control arms at 2" of lift. Cleared the differential fine (Dana 44). This is at full bump.
Click to expand...

Thank you Mike. That looks like a lot of clearance. How much bumpstop extension do you have in that photo?
 
The 'approved list' I was referring to is a very lengthy thread on another forum. In that thread it came down to JKS, Currie or Metal Cloak that were the only ones that fit. I took a chance and it didn't work.

Since it looks pretty clear from Mikes photo that the JKS clears his Dana 44 with ease, I don't feel so bad to call out the company now. I just didn't want to bad mouth a company if it was my mistake and not theirs. The track bar I purchased is the new Rancho track bar with the D2 bushing. I understood that this was a new design, so I had hoped that it would work. The track bar is very well built, but the bends are really bad. You can see in the picture below a black spot on the diff cover where the track bar has already hit once or twice. That is with 2" of bumpstop. I weighed the front of the jeep down and found I would need 4" of bumpstop to keep it from hitting with stock length arms. I don't think I could make my arms short enough to make that fit.

IMG_20200412_174353.jpg


Juggernaut said:
For question #2 : I don't think anyone can tell you really what your castor angle should be for your setup. The driveshaft angles take precedent over actual castor measurements. So start with angles and castor largely is what it is. Aim for zero difference between the driveshaft and pinion yoke and the castor should feel ok. For what it's worth, I run 35's with equal angles and it turns out to be just about 5 degrees castor with good road manners and steering return. Larger tires can get away with less castor. If you aim for 7 degrees castor with a suspension lift, your pinion yoke is going to be way low and you'll almost certainly have vibes.
Click to expand...

Thank you. I thought it seemed wrong to adjust for trackbar room while ignoring driveshaft angle. But that was the advice from the Rancho tech.

Juggernaut said:
For question #1 : When you say the track bar will hit the diff cover - does that mean rubbing contact or snap in half contact? Stock diff cover I assume?
Click to expand...

Stock Rubicon dana 44 diff cover. You can see in the picture above that would either snap the shaft or put a dent in the diff cover so big the ring gear would hit it. Or snap the bar when it hits the ring gear.
 
Fargo said:
Thank you Mike. That looks like a lot of clearance. How much bumpstop extension do you have in that photo?
Click to expand...
I have about a half inch of extra bump stop up front.

Looking at your picture, it appears that the track bar needs to roll forward. What type of joint is on the frame end?
 
I'm assuming in the picture that the axle end of your bar is a fixed joint so the bar cannot be rotated to make the bend more useful or provide more clearance. Correct? I'd have no issue shortening the arms a bit to clear a minor interference, but it looks like a lot more clearance is needed and your right not to follow the advice to ignore drive line angles to make the track bar work. That's just bad. Again it looks like solid interference in the pic but I cant tell exactly how much. Have you cycled the suspension through (less springs) to see exactly? The axle does slightly travel fore and aft as the suspension moves through a slight arc. Just something to consider when looking at arm length and interference.
 
Mike_H said:
I have about a half inch of extra bump stop up front.

Looking at your picture, it appears that the track bar needs to roll forward. What type of joint is on the frame end?
Click to expand...



Juggernaut said:
I'm assuming in the picture that the axle end of your bar is a fixed joint so the bar cannot be rotated to make the bend more useful or provide more clearance. Correct? I'd have no issue shortening the arms a bit to clear a minor interference, but it looks like a lot more clearance is needed and your right not to follow the advice to ignore drive line angles to make the track bar work. That's just bad. Again it looks like solid interference in the pic but I cant tell exactly how much. Have you cycled the suspension through (less springs) to see exactly? The axle does slightly travel fore and aft as the suspension moves through a slight arc. Just something to consider when looking at arm length and interference.
Click to expand...


Only 1/2" bumpstop, thats impressive.

The axle end of the track bar uses a DDB style bushing (Rancho D2). So its similar to the factroy Clevite. The frame end uses the same type of swivel joint as the factory track bar had with the tapered bolt. One of the reasons I liked this trackbar was because it used a tapered bolt and I didn't have to drill out the frame. So there is really no way that i can rotate the track bar to make any room.

I have not pulled the springs yet to cycle through. I was going to put in some taller 3" srpings and do that when I did my fine tuning. The way the track bar is now its so far off and contacting so hard, I didn't feel the need to go any further. I did consider the fore/aft movement of the axle as it cycles through its range, but I thought on compression it moved the axle forward into the bar even more. So again I didn't check further.

Unless I can get Rancho to refund my money on a 1 year old track bar, I guess I have no choice but to eat my loss and buy a different track bar or spend a couple weekends fooling with arms. Afterwhich I expect I will find they don't work and I will have to eat my loss and the lost time I now have invested.

How will shortening the arms affect bump stop alignment? Or does that become an issue when I rotate the pinion?
 
Fargo said:
....

How will shortening the arms affect bump stop alignment? Or does that become an issue when I rotate the pinion?
Click to expand...

As long as the cup makes good contact with the pad, the alignment is good enough. This is one reason I am liking Currie bump stops. They allow room for more adjustment.
 
Fargo said:
Only 1/2" bumpstop, thats impressive.

The axle end of the track bar uses a DDB style bushing (Rancho D2). So its similar to the factroy Clevite. The frame end uses the same type of swivel joint as the factory track bar had with the tapered bolt. One of the reasons I liked this trackbar was because it used a tapered bolt and I didn't have to drill out the frame. So there is really no way that i can rotate the track bar to make any room.

I have not pulled the springs yet to cycle through. I was going to put in some taller 3" srpings and do that when I did my fine tuning. The way the track bar is now its so far off and contacting so hard, I didn't feel the need to go any further. I did consider the fore/aft movement of the axle as it cycles through its range, but I thought on compression it moved the axle forward into the bar even more. So again I didn't check further.

Unless I can get Rancho to refund my money on a 1 year old track bar, I guess I have no choice but to eat my loss and buy a different track bar or spend a couple weekends fooling with arms. Afterwhich I expect I will find they don't work and I will have to eat my loss and the lost time I now have invested.

How will shortening the arms affect bump stop alignment? Or does that become an issue when I rotate the pinion?
Click to expand...
You could always cut the trackbar in half, rotate the bend forward, sleeve and re-weld. :)
 
Mike_H said:
You could always cut the trackbar in half, rotate the bend forward, sleeve and re-weld. :)
Click to expand...

That is beyond my skill level. The other issue is that the bend doesn't even look like its in the right place. Its about 6" to far to the passenger side.

IMG_20200412_174327.jpg
 
One more thought / observation - from the pic above, you don't seem to have a lot of thread showing on the adjustable end of the track bar. Are you certain the axle is centered correctly? It still looks like a lot of interference regardless but I was wondering if the bend offer more clearance if the axle was shifted towards the passengers side. It seems like you've already made that observation about the location of the bend in the bar. Might be worth confirming the axle is correctly centered.
 
I think I already pushed it over the the passenger side further than needed to make room for a 1" taller lift.
 
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