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.

 

[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*.

 

[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...

 

[lars]

@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...

For what it's worth, even though I have occasionally hammered on my Bronco off road and have used it for decades as a campmobile, most of the miles I've put on it have been on pavement getting to the starts of my offroad adventures. A lot of long distance travel. And that's where the stability of self-centering steering has mattered the most to me, and why I went through the trouble of the cut n' turn. It's exhausting to drive for 10-12 hours at speed in a vehicle that requires constant attention to keep in the lane.

 

[DirtDonk]

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.

And I’ve said that more than my fair share of times.
However, I don’t believe that I’ve spent much time harping on the “variances“ between caster readings. As much as I have that they all seemed lower than expected, except for an occasional 76 or 77 front end that is.
Lars’ 77 excepted.

The problem for many years is that very few people ever measured their caster at stock height with stock bushings. All the measurements came after various height lifts and big tires and different variations of the c-bushings were already installed. And after the complaints about how poorly they drove started.
So there was really no way to accurately gauge how they were from the factory. Unless someone took the time to measure from the points you mentioned. Which we have rarely done in the past.
Be nice if we can now start doing that, knowing there is a consistent spot to measure from, to get an expected result in the caster department.

 

[ntsqd]

For what it's worth, even though I have occasionally hammered on my Bronco off road and have used it for decades as a campmobile, most of the miles I've put on it have been on pavement getting to the starts of my offroad adventures. A lot of long distance travel. And that's where the stability of self-centering steering has mattered the most to me, and why I went through the trouble of the cut n' turn. It's exhausting to drive for 10-12 hours at speed in a vehicle that requires constant attention to keep in the lane.

Occasionally? Was swmbo reading that over your shoulder?
The statue of limitations has passed by now, so should be safe to post these. This is what "hammered on" looks like:

And this is what it took to stay in range (note the number in the upper left of the display):

To be fair, that is my GPS, I'm just as guilty.