Another Caster Question...

[DirtDonk]

To be clear here though, even the modern stock replacements are so poorly made that they are no longer able to achieve proper preload with the normal method.
Sometimes you have to wing it. But it’s always with the end goal in mind of proper pull-torque on the knuckle.

 

[Torkman66]

I'll poke around to see where that article was regarding preload. Seems like if you are supposed to screw it in to 1/8" BELOW yoke lip then that instruction alone deletes the preload requirment. Preload is set by how far and with what pressure the sleeve is pressed against the balljoint. If you arbitrarily stop at 1/8" below, how is that taking into account setting preload?

 

[DirtDonk]

No, you are absolutely correct about that.
They probably used that 1/8 inch as pretty much a generic, standard depth that used to be commonly achieved when setting preload.
And as I mentioned, even with standard replacements, the preload torque that you used to get on the spanner wrench is typically not achievable any longer.

The book calls for 40 pounds if I remember(?), but most of the time, by the time you reach 20 pounds, you’re already halfway through the yoke and out into the open air underneath!
So yes, it is a relative thing. But I still say that at least trying to get the preload close to correct, is still a best practice.

 

[Torkman66]

Sounds right. Going out to work on it now.

 

[DirtDonk]

To add to what I just said, getting at least close to the specified torque rating, while still a best practice, testing the pull-torque at the end is, to my mind at least, still an absolute necessity.

 

[DirtDonk]

If you get to the point of redoing the upper sleeve, if you don’t mind a little extra work, (I know easy for me to say!) disconnect the tie-rod as well, and check the pull-torque as it sits right now.
Then recheck it after the new adjustment procedure.

 

[Torkman66]

I went out and lowered the sleeve into the yoke. I reached 40ft#s before the sleeve was in the proper location to increase caster (Slot facing back) so went ahead and tightened it to proper location. Preload is closer to 50. The movement of the spindle with tire off is still very doable, firm, but not difficult to move by hand without tire on so I think torque is likely OK. Same on each side.

Did another test drive and surprisingly it drove noticeably better...imagine that, install part correctly and it works better. So while it is good enough now to drive it to the alignment shop without wondering into on-coming traffic, it still is drifting and not super enjoyable to drive. My guess is that it has about 3 or 3.5 caster. We will see tomorrow and report back. If that is the case, seems the easiest fix will be the T-Rex arms. Like previously mentioned, the stock arms I have on it were not in the greatest shape and should have been replaced earlier.

 

[DirtDonk]

Interested to find out what the reading is.
If you do get the arms, don’t be surprised if the front driveshaft won’t bolt back in with the 7° bushings.
Maybe you’ll get lucky though, and when they tweak the toe in (if needed), maybe it’ll drive even better still.

I’ll run down the dry steering test in a bit. Phone battery is dying.

 

[DirtDonk]

I went out and lowered the sleeve into the yoke. I reached 40ft#s before the sleeve was in the proper location to increase caster (Slot facing back) so went ahead and tightened it to proper location. Preload is closer to 50.

Whenever something like this happens, you can also back it off slightly to achieve your adjustment.
I don’t think which direction to go, looser or tighter, matters as much as the final result. But my tendency in something like this would’ve been to back it off slightly to get the proper caster. Rather than tighten it.
But it sounds like you’re right on the money at this point!

 

[Shimmy]

i'm probably stating the obvious but as you adjust the caster thru those sleeves, the camber is being adjusted too.

the sleeves are for very fine tuning of camber and caster. imo they shouldn't be used to achieve caster goals of a truck that's wandering.

 

[ntsqd]

Unless you use the double-adjustable inserts. Which I'm told frequently cause more pain than the cure.

 

[jamesroney]

@Shimmy Thx. Yea, before I worked on the toe this morning it was pointed up more...I'll take care of that. Thanks!
Talked to Duffs about options. Their T-Rex arms sound like the way to go. I have the original arms and to be honest they are not great anyway. Should have replaced them during the build. He said the arms will give me another 3 to 3.5* caster. That will likley be just right. I'll get the actual alignment numbers tomorrow to see what I need. With the T-Rex may be able to go down to the 4* bushings. As noted, tradeoff in all of this is the pinon angle. But this is a show/street Bronco. While it will not see offroad use, I still want the 4wd to be functional. Will know so much more tomorrow.

Keep in mind that the T-rex arms are not superior to the original arms, and provide no benefit when you finally cut and turn your D44.

Before you go to the alignment shop, you will want to measure the distance between your axle and frame both front and rear. When I look at the profile pic of your Bronco, I see quite a bit of rake. Every degree of rake takes away from caster. Your alignment shop will not take this into consideration.

When your pinion angle is wrong, the CV joint at the transfer case binds first, and prevents articulation.

If you can put a protractor on your D44 front cover, I can tell you your caster. My guess is your 3 degrees is about right based on how it drives.

Obviously, adding those eccentrics in the knuckle only makes things more complex. Hopefully your camber numbers will be correct. But you need to get the camber correct first.

 

[jamesroney]

i'm probably stating the obvious but as you adjust the caster thru those sleeves, the camber is being adjusted too.

the sleeves are for very fine tuning of camber and caster. imo they shouldn't be used to achieve caster goals of a truck that's wandering.

I'll go one step farther...the sleeves are for camber correction of bent housings. They shouldn't be used for anything else.

 

[Torkman66]

@jamesroney the rear is 1" higher than the front. I have already removed the #3 leaf and the small one just to get it down to what it is. Not sure why the rear leaves created such a rake (or I suppose, although new, the front coils could be low). The angle that the rear of the diff makes using two of the vertical bolts is 99*. To be clear, if looking at the diff from the drivers side front wheel in, the backside of the housing tilts back past the 90* point 9* more. Total of 99*.

 

[jamesroney]

@jamesroney the rear is 1" higher than the front. I have already removed the #3 leaf and the small one just to get it down to what it is. Not sure why the rear leaves created such a rake (or I suppose, although new, the front coils could be low). The angle that the rear of the diff makes using two of the vertical bolts is 99*. To be clear, if looking at the diff from the drivers side front wheel in, the backside of the housing tilts back past the 90* point 9* more. Total of 99*.

I usually end up running 3.5 front coils with 2.5 rear leaves to get them to sit right. Especially with a front winch, and no hardtop. That's why I recommend measuring the as-built lift between frame and axle tube.

I don't understand this: "The angle that the rear of the diff makes is using two bolts is 99 degrees" Are you talking about the Front diff, and the front cover? So the angle that the front cover on the front diff is 99 degrees?

If so, then you are almost exactly where the stock axle was. From the factory, the front cover sits at ~8 degrees, the caster is ~4 degrees, and the radius arm is dead flat.

Your cover is at 9 degrees, so the caster is 3 degrees, and the wedges are 1 degree tilted up. plus 7 degrees of c-bushing puts your radius arm at 8 degrees up.

But you added a degree in the ball joint...so now it's about 4 degrees of caster.

You will hear that all bronco's are built a little bit different. But I've measured at least 20, and I think they are all about the same.

 

[Torkman66]

Yes, that is how I measured it. Sry for not explaining myself very well. I’m anxious to see what it is tomorrow. Seems 4* would be ok. But it sure wanders. I’ll see what it is and might just bite the bullet and cut the Cs to do it right. I’ll report back.

 

[DirtDonk]

Caster is a main culprit, but it’s never the only, or sometimes even the main culprit.
As I’ve said many times here, my 71 has less than 2° on one and just over 2 on the other and it tracked straight and true its whole life.

I never measured caster when it was stock height. I didn’t measure when it was 1 1/2 inches of lift with stock c-bushings, or 2 1/2 inches of lift with stock c-bushings. I only measured after it was 3 1/2 inches of lift with 7° c-bushings.
I’m sure I’ll come across the printout again sometime so I can quote the exact numbers. But they were pretty low, which led me to believe that it didn’t have the specified settings even from the factory.
As has been the experience of many others here over the years as well.

So while it is a culprit, we always have to look at the entire package and optimize everything.
Sounds like you’ve already done most of that, but maybe something is still missing.
And maybe that something is as simple as getting that alignment checked.
Well, we can hope anyway!

 

[lars]

After I installed a 1977 Dana 44 into my otherwise box-stock (no lift or any other suspension mods) using what I was told were 2° urethane radius arm bushings, I took it to an alignment shop. They measured about 1-1/2° of caster. In 2003, after 5 years of various lifts and monkeying around with different C bushings, eccentric upper ball joint bushings etc, I got disgusted with fighting the wandering. Heard about inner C cut n' rotate. What a PITA. Worth every minute of effort. Wound up with 6°. Magic. Handles like a modern 4x4. In fact better than my neighbor's 2019 Jeep Rubicon. Ok, maybe that's a low bar but you get the idea.

And yes, before I resorted to that I tried all the other mentioned fixes- tires, toe in, tire pressure, etc.

 

[Torkman66]

Agree all. Here is a question. Other than installing the bushings wrong (placed in wrong position) are there other ways to install them wrong? I know they were extremely hard to get on and required a long bolt to get the short ones started. But is it possible to tighten down the arms in such a way that they are "out of place" mounted somewhat rotated such that the 7* in the bushings are lost in the misalignment? Or, does the bushing automatically find its way home, so to speak, when they are tightened up? Just grasping here. Even thought of maybe trying to loosen the arm caps a bit and try to pull the pinon down (increasing caster) and then retighten the caps. Not sure that even works.

 

[Torkman66]

@lars I hear you...once I get the numbers tomorrow at the alignment shop, I'll have a better idea of what I am dealing with. Considering this truck will never see a dirt road (it was built to be a show Bronco and pleasure street ride), the front pinon angle is not too much of a concern...but drivability is. If I can fix the caster with T-Rex arms that might be the easiest solution...they would likely get me 3* more or so. However, if the numbers are so far off (say 1 or 2* total castor), then I will bite the bullet and do the cut. While the axle is totally finished and powder coated, I think I could still remove the Cs, rotate to best castor position, and weld them back on without disturbing more than 3 or 4 inches of the powder coated areas at the axle weld locations. I could then just paint in a gloss black to match the axle and be done with it. It is what it is...