C-bushings, caster, and touchy touchy steering

bentendo · Apr 4, 2012

Hey fellas,

Just finished up the mechanical work on my '72, which included a 3.5" James Duff ultimate suspension lift. Since lifting, the steering can best be described as "scary" going down the highway.

I've checked out multiple threads on here, and after taking it to an alignment shop, they told me my caster was out -2.0º on both sides. The Duff kit came with 4.5º bushings I believe… and I'm POSITIVE I put them in correctly (marked for front/rear top/bottom on the bushing).

My question is: do I need to upgrade to a 6.25º or a 7º to get my caster into the positive? I can't live with the steering as-is, my deathwish impulse just ain't that high %)

Thanks,
Ben

EDIT:
My setup for the steering includes a brand new power steering conversion kit from Tom's, brand new linkage, new steering dampener, new ball-joints

Bronco Junkie · Apr 4, 2012

I have a 2.5 inch Duff lift on my 1973. I bought my kit in 2005 and before you installed the "C" busing you were supposed to cut off a little "nipple" looking thing on the apex of the bushing. I did not do that the first time and my alignment was off. Did you need to cut off that little dohicky?? After I did that, it was all good.

gr8scott · Apr 4, 2012

Definitely go with 7º bushings.

broncnaz · Apr 4, 2012

Most 3.5in lifts come with the 6 degree bushings but if you put in 4 degree bushings then you'll see a differance with a swap. Of course you'll jst be at zero and ideally you want about 4degrees.
broncos came from the factory with terrible caster angles and lifting causes things to get worse. sometimes you cant get enough caster with any bushings in which case you have a few choices on possible fixes you can have the knuckles cut and turned, install extended radius arms or install radius arm drop brakcets.

aliensecretion · Apr 4, 2012

Just went through this with my 2.5" lift. 4º bushings didn't do anything. 7º was a very noticeable improvement. Fixing and reinforcing the frame was like a new car!

NYLES · Apr 5, 2012

gr8scott said:
Definitely go with 7º bushings.

x2 sevens is good fer it!

bentendo · Apr 5, 2012

Thanks fellas! 7º bushings it is… I'll keep y'all posted on how it turns out

dave67fd · Apr 5, 2012

The Duff 3.5" ultimate kit comes with the 6.25 deg. bushings unless you purchased all of the parts seperately and bought the 4.5's.

I would like to think even then they would have recommended the 6.25's or the 7's.

bentendo · Apr 5, 2012

Well, I definitely got the ultimate kit, but the bushings read 4.5º on one side and 6.25 or 6.5º on the other. They're also marked "front bottom" and "rear bottom", so I installed them according to their markings.

I'm a newbie with all this, but seems like those are their 4.5º bushings that they sent… am I right?

maverickconner · Apr 5, 2012

definately go with the 7 degree bushing or drop the radius arm brackets. The road walking is horrible if you don't

bentendo · Apr 5, 2012

Well… just called Duff's. The tech there said that factory caster settings varied quite a bit, and that the wedges on my front end were probably placed out of spec originally. Also confirmed that i received the 6.25º c-bushings and that normally that would've gotten me positive caster…

He's recommending a combo of an adjustable bracket for the radius arms and 7° c-bushings. Any thoughts?

surfer-b · Apr 5, 2012

I would throw the 7's in and give it a try, I run them on 2.5" and have good results. You may have to add even more caster. I have used these http://www.rockauto.com/catalog/moreinfo.php?pk=274804
http://www.rockauto.com/catalog/raf...08&partkey=274804&a=FRc1413784k274804-7000556
and have had good results with no probs, some of the members don't like them, however I have never had any probs.

bentendo · Apr 5, 2012

What type of ball joint sleeve and knuckle bushing am I looking at there, surfer-b? Do those change caster at the knuckle somehow?

broncnaz · Apr 5, 2012

Your only going to get a max of 1 1/2 degree with the ball joint bushings. I would swap your C bushings first. Then if you need/want that extra degree go for the ball joint bushiing.

dave67fd · Apr 5, 2012

bentendo said:
Well, I definitely got the ultimate kit, but the bushings read 4.5º on one side and 6.25 or 6.5º on the other. They're also marked "front bottom" and "rear bottom", so I installed them according to their markings.

I'm a newbie with all this, but seems like those are their 4.5º bushings that they sent… am I right?

Give Duffs a call and explain. Maybe they can shed some light.

DirtDonk · Apr 7, 2012

The Duff guy is right about the inconsistency of the axles and how much or little caster was originally built in. But... If you're actually running at -2 degrees, you've got one of the worst cases of mis-aligned pads from the factory that I've ever heard of.
Usually, the only way to get that far negative with new radius arms and 6.25 degree bushings is by putting them in backwards.

I know you said you got them in right, but it wouldn't be the first time even the experts put them in backwards even after reading them twice!
If you've indeed got the 6.25's now, then replacing them with 7's is only going to net you an additional 3/4 of one degree. Taking you from negative-2, to negative 1.25 degrees. Nowhere near the more desirable positive area. A good "minimum" reading for you would be +4 degrees. And that's going to take an additional 6 degrees from where you are now!
Unless by "out -2" the alignment guy meant you were 2 degrees below optimum? But if he meant you were at "negative 2 degrees", then you're hosed.
If your bushings are in correctly, and you indeed have a negative two degree caster reading, the only way you're going to get anywhere near an appropriately safe caster value is to cut the steering yokes ("outer c's") off the ends of the axle tubes and rotate them back at the top.

Frankly, I hope you have your bushings in backwards. It's a pain, but it's cheap to fix!

Good luck.

Paul

bentendo · Apr 8, 2012

Thanks Paul, urr-body,

I'm about to disassemble the front end per Heus33's excellent bushing installation write-up. Stay tuned, when I get to the actual c-bushing removal I'm going to post some photos to make sure they're installed correctly.

As always, feedback is appreciated! Gotta keep a newb like me in check

-Ben

croft75 · Apr 8, 2012

I had the same problem last spring, with my 3" lift had the same castor numbers as you, I went to the 7* it improved the drive but if yours was as scary as mine on uneven roads or under braking it will only improve it. I am going to be rotating the knukles this spring 9-10* to make it better to drive.

bentendo · Apr 8, 2012

Okay fellas,

Got the front end apart, and double checked my c-bushings… they were definitely installed correctly. The only thing that was a possible red-flag was on the rear bushing it looks like I forgot to shave off the casting nub and it smooshed into place rather than set up properly on the axle-housing wedge. (see pictures)

I'm going to dremel out the remainder of that nub then button it all back up… however, unfortunately, it looks like I'll definitely have to install drop brackets, 7º bushings, AND possibly the caster-adjust sleeves at the knuckle.

What do y'all think? I'll pick up .75º from the new bushings, 4º from the drop bracket, and another 1.25º from the knuckle sleeves… which should net a total of +4º of caster when finished.

Shout out with your opinions, I have some decisions to make!

Thanks again all,
Ben

Note: pictures don't show it, but I *did* remove and double-check the REAR bushings as well.

bentendo · Apr 8, 2012

One more thing, here's my readout from the alignment shop:

C-bushings, caster, and touchy touchy steering

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