Caster and front driveshaft

[the74bronco]

Has anybody added caster over and beyond the 7 degree bushings (radius arms or drop brackets) without front driveshaft issues? I need more caster and I’m looking for options before I go the cut and turn route. I already had to clearance my front driveshaft once.

 

[Apogee]

I had pinion angle issues with a 3.5" SL and CAGE long-arms on my '77 running the 4 degree bushings, and 7 degree bushings would have been preferred from a caster perspective, but would have bound at ride height. As it was, I could limp around with an offset front u-joint and live with the vibrations so long as I didn't flex it out too hard in droop.

That's been my weak link for years, so I'm finally swapping out the front D44 for a 65" full-width HP D44 ('76 F150 w/ welded wedges). Since I'm going through the effort, I figured I may as well turn the knuckles and relocate the radius arm wedges for pinion angle and caster numbers I want, versus the best compromise I can make happen with how it is. While not a small job to do so, better to do it now than to wish I'd done it later.

FWIW, those C's are pressed onto the tube super tight and have a pretty serious weld, but I now have a crack all the way around on both of them and will be putting a lift kit on my 55-ton press this weekend so that I can press off the C's directly...I don't think my BFH is big enough. Once that's done and I've gotten everything cleaned up, then I'll begin mocking it up under the rig so that I can get everything set at ride height where I want it.

Given your specs of a 5.5" SL, just turn the knuckles already

 

[the74bronco]

I wish I would have went the hp d44 route, but it’s a little late now with being re-geared with an ARB. I looked at the offset u joint as well, but I have to run in 4wd on the highway in the winter to keep things tracking straight. Have you gotten an alignment? What were your caster readings? I’m sitting at basically 0 degrees with the 7 degree bushings.

 

[Apogee]

Before I did my CAGE 3.5" lift, there was a hodge-podge of stuff the previous owner had done, but it drove pretty well with about 2.5 to 3 degrees of caster and 33x12.5 tires, but didn't return to center as hard as I'd have liked, especially for small steering inputs.

After the CAGE 3.5" lift, long-arms and 4 degree bushings, I gained about 1.5 degrees of caster and it drove quite well so long as I kept it in 2WD. In 4WD, the front pinion angle issue became readily apparent at anything over 10-15 MPH, and I avoided running around in 4WD at speed due to the unsettling vibration coming from the front shaft.

Since you're going to be running in 4WD at speed on the highway for extended periods of time, I'd again suggest that you turn your knuckles and fix both your caster and pinion angles at the same time so that you can just be done with it. Keep in mind that you may need to rework your track bar mounts at the axle end when you roll the pinion up...I'm swapping in a different axle, so track bar mounts and steering linkages were already on the list for me.

 

[jamesroney]

I don’t understand the question. C-bushings are only a cheap way to avoid rotating wedges. The total angle between the inner c and the pinion inclination is defined by the way the inner c is welded to the tube. If you want proper steering, and proper u-joint angle, then you have to cut and turn. The only time that isn’t true is if you run an early bronco 2 inches lower than stock.

Even the high pinion D44 needs to be cut and turned at 3.5 inches of lift. I just did this 1977 HP44, and it needed 4 degrees of correction.

 

[the74bronco]

If I cut and turn the front axle. What should my target caster be?

 

[Apogee]

If I cut and turn the front axle. What should my target caster be?

I would consider 5-8 degrees caster to be ideal depending on tire size and width.

 

[blubuckaroo]

If I cut and turn the front axle. What should my target caster be?

According to Chiltons, the big 78/79 Broncos call for a 6.5 to 9.5 degree caster.
If you're power steering and pinion angle are good, that's what I'd shoot for.
That should make a great tracking Bronco.

 

[Broncobowsher]

I once saw a CV at the front pinion.

 

[blubuckaroo]

Kudos to you the74bronco. In the past, I've had a number of our members poo-poo the necessity of a good front pinion angle. Some will sacrifice the road use of 4WD just so they can cheap out and use high angle 'C" bushings. That may work for trailered rigs and mall cruisers, but if you use 4WD to get to work, you need a good front pinion angle.

 

[the74bronco]

I once saw a CV at the front pinion.

I have looked at the Toyota front driveshaft mod, but for the cost I can almost complete a cut and turn. I’m not sure the Toyota driveshaft will handle the power with the locker. At least the Ford one is cheap to replace.

 

[the74bronco]

Kudos to you the74bronco. In the past, I've had a number of our members poo-poo the necessity of a good front pinion angle. Some will sacrifice the road use of 4WD just so they can cheap out and use high angle 'C" bushings. That may work for trailered rigs and mall cruisers, but if you use 4WD to get to work, you need a good front pinion angle.

I see a lot of people go back to stock or 4 degree bushings with a cut and turn. Is the reason just to have some future adjustability?

 

[the74bronco]

I would consider 5-8 degrees caster to be ideal depending on tire size and width.

Do bigger tires = more or less caster?

 

[reamer]

I cut the weld at the knuckles from the tube, then Rotated the knuckles with a BFH and re-welded to the knuckles to the tube, this way I go the caster right and kept the original front shaft angle.
My knuckle on left side was welded to the tube with 0 caster from the factory....

 

[garberz]

Do bigger tires = more or less caster?

Bigger tires require less caster. But like Apogee said, “anywhere between 5-8* is ideal”.

Mark

 

[Apogee]

I see a lot of people go back to stock or 4 degree bushings with a cut and turn. Is the reason just to have some future adjustability?

I'll change back to a set of 2 degree urethane bushings when I turn my knuckles, that way I have +/-2 and +/-4 degree adjustability with available C-bushings, not that I expect to need it. That said, the 2 degree bushings have more material between the wedge and clamps/radius arms, so they seem more robust to my eye...whether that's true or just my gut intuition, that also factored into my reasoning.

FWIW, it took 40-tons of force in the press to knock off one of the outer C's after I took off the weld and had a crack all the way around...the other came of with a bit less at 25-ton or so

 

[lars]

I'll change back to a set of 2 degree urethane bushings when I turn my knuckles, that way I have +/-2 and +/-4 degree adjustability with available C-bushings, not that I expect to need it. That said, the 2 degree bushings have more material between the wedge and clamps/radius arms, so they seem more robust to my eye...whether that's true or just my gut intuition, that also factored into my reasoning.

FWIW, it took 40-tons of force in the press to knock off one of the outer C's after I took off the weld and had a crack all the way around...the other came of with a bit less at 25-ton or so

Those things are on there. I did mine 16 years ago and I still remember sweating that. I also used 2 degree urethane bushings, based on the same logic. I checked them a couple of years ago, and since they were still in good shape I returned them to service.

I wound up with 6 degrees of caster and the pinion angle where it should be. What a difference. Cut and turn just puts the geometry where it would likely be if Ford were building that axle/lift combination now.

 

[bchesley]

To do this correctly you have to pull the knuckles off then install the axle with the pinion pointed where you want it. Then you reinstall the knuckles with the desired caster and weld them on. That is the only way to do it right. If you have a steering over knuckle set up you can rotate the knuckle about 10 degrees before you get in to the factory brackets when you turn. That is what I did and I have 7 degrees of caster with an almost perfect pinion. I am running duff arms with the bushings in backwards to retard the rotation built into the duff arms. The only thing that takes a while is you have to pull the axle out twice. The cut and turn part was about 1.5 hours of time. I will say this is my third axle to do it to so it goes faster the more you do. I have a great thread full of picture if you search.

 

[Broncobowsher]

You can zero a poly bushing. Install one half upside down. So both the thick parts are on top (or bottom).

 

[Spaggyroe]

To do this correctly you have to pull the knuckles off then install the axle with the pinion pointed where you want it. Then you reinstall the knuckles with the desired caster and weld them on.

Assuming you have to cut the radius arm mounts off the axle too, in order to set the pinion angle?

Thx