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Discussion Starter #1 (Edited)
My early bronco drives like $hit. I've done everything I can to get as much caster out of it as possible. I pretty much wander down there freeway white knuckling it the whole way. My only option at this point to gain more caster is to rotate the yokes on the axle backwards. The problem is I can't find much info on what the front drive line geometry is supposed to be. I have a double cardan joint drive shaft in the front. Currently my front axle pinion is pretty much parallel to the ground or possibly pointing a few degrees down. Is this correct? Every diagram I see with double cardan drive shaft is for the rear and shows the pinion pointing directly at the the transfer case. I don't see how this is possible in the front because of all the steering components. Can someone educate me?

I have read the tech article on driveshaft geometry, its just not making sense...

Possible relevant info.
3.5" Lift
6* bushings (Assumption. Installed by previous owner)
33" Tires
Power Steering

Thanks!
Blake
 

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Point pinion at tcase output and then drop down like 3* to account for axle wrap. Cut outer c's off of the tubes and rotate them to set caster at 7* or so with the pinion sitting where it needs to be.

3* would be for leaf springs, probably dont have to go that much for radius arms
 

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Discussion Starter #3 (Edited)
Point pinion at tcase output and then drop down like 3* to account for axle wrap. Cut outer c's off of the tubes and rotate them to set caster at 7* or so with the pinion sitting where it needs to be.

3* would be for leaf springs, probably dont have to go that much for radius arms
This is for the front axle? Wont the pumpkin interfere with the steering components if rotate it that much?

Does that mean I have to rotate the wedges the radius arms bolt around too?
 

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Im not sure of your setup. I ran a 79 ford d44 that i rotated pinion up 8* iirc then cut and turned the outer c's to set the caster where i wanted. I was running high steer and didnt have any issues.

What year is your bronco?
 

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Discussion Starter #5
Im not sure of your setup. I ran a 79 ford d44 that i rotated pinion up 8* iirc then cut and turned the outer c's to set the caster where i wanted. I was running high steer and didnt have any issues.

What year is your bronco?
1974.

I could be completely wrong here, but I don't think even putting in zero degree radius arm bushings would get my pinion to point anywhere close to the TC yoke.
 

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If your pinion is pointing down, you already have more caster than a lot of broncos.
Can you post up some pics?
You only cut and turn an EB if you need more caster and want a better driveline angle as well.
With only 3.5" of lift, you should not be having those issues.
 

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1974.

I could be completely wrong here, but I don't think even putting in zero degree radius arm bushings would get my pinion to point anywhere close to the TC yoke.
You can run the C bushing upside down to rotate the pinion up, but unless the radius arm mounts are dropped, the 0* bushings should put the pinion in the right relationship with the T-case as it was stock.
 

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You need to pull apart radius arm and see if bushings were installed correctly. Seems to me that their backwards. Again you shouldn't be having caster issues with only 3.5" of lift pictures would help.
 

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Discussion Starter #9 (Edited)
You can run the C bushing upside down to rotate the pinion up, but unless the radius arm mounts are dropped, the 0* bushings should put the pinion in the right relationship with the T-case as it was stock.
Good to know that its possible to run the bushings upside down. I do have dropped radius arm mounts installed by the previous owner.
 

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Discussion Starter #10
You need to pull apart radius arm and see if bushings were installed correctly. Seems to me that their backwards. Again you shouldn't be having caster issues with only 3.5" of lift pictures would help.
I wouldn't put it past the previous owner on doing something like this, but looking at the pinion angle I don't see how that could be the case. I'll get some pics under the truck this weekend.
 

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I do have dropped radius arm mounts installed by the previous owner.
Sounds like your 6* C bushings are too much with the dropped brackets and only 3.5" of lift. I would think 2-3* would be closer to what you need.
 

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Discussion Starter #12 (Edited)
Sounds like your 6* C bushings are too much with the dropped brackets and only 3.5" of lift. I would think 2-3* would be closer to what you need.
Here is what my caster was with all mods listed.

Driver = 3.27
Pass = 2.46

I now have ball joint bushings, I have not gone back to the alignment shop but based on what I installed and how I installed them. I should be somewhere around the following.

Driver = 3.27 + .75 = 4.02
Pass = 2.46 + 1.5 = 3.96
 

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A few other things to check that haven't been mentioned.

Is the steering linkage in good condition?
Are the radius arm and track bar bushings in good condition?
Dose the steering box have excessive play?
Is the frame cracked at the steering box?
Does it have a dropped pitman arm and/or dropped track bar bracket? (If it has one but not the other, you'll get bump steer.)
If it has a drop bracket, is it solidly welded?
 

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Discussion Starter #14
A few other things to check that haven't been mentioned.

Is the steering linkage in good condition?
Yes, from what I can tell. Anything specific to look for?
Are the radius arm and track bar bushings in good condition?
Yes, track bar is brand new bushings look great.
Dose the steering box have excessive play?
I don't have much to compare it to except my 2011 tahoe. When comparing to that yes it does.
Is the frame cracked at the steering box?
Nope
Does it have a dropped pitman arm and/or dropped track bar bracket? (If it has one but not the other, you'll get bump steer.)
I have both. No bump steer what so ever. Trackbar and a drag link are perfectly parallel. Also, I have brand new 1 ton chevy steering in stock location.
If it has a drop bracket, is it solidly welded?
Yes, checked that also when replacing the trackbar.
 

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Sounds like your 6* C bushings are too much with the dropped brackets and only 3.5" of lift. I would think 2-3* would be closer to what you need.
Yeah I installed Iirc 6 or 7 degree bushings on my truck when I ran dropped radius arm brackets and they they were too much.
 
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