Bronco Lean - Would Diagnosing C Bushings With Jackstands Work?

[the-glove]

My 67 leans to the passenger side quite a bit, more in the rear than front. I’m aware of the affect the C bushings and the torquing of the cap bolts can have on lean. Before I go into the whole taking apart the front end, leveling the radius arms and torquing down the radius arm caps in the X pattern, I was thinking….wouldn’t an easy way to diagnose or rule out the C bushings/caps as the culprit be to take off the front wheels and put the front frame on jackstands? This would take away the impact the front suspension has on any lean right? If this takes away the rear lean, it means it likely is the c bushings/caps causing it. If it’s still leaning, that probably means it’s something else. Would this work? Thanks in advance!

 

[DirtDonk]

Never tried it, but your logic seems sound.
If you can get the frame horns at the same distance above the ground, you should be able to determine if some of the sag is in the rear springs.
Which does happen, of course, as leaf packs do very often settle down over the years.

I would start off by taking measurements at all four corners, between the tops of the axle tubes, and the bottom of the frame rails.
Just to give yourself a point of reference.

But also check all eight body mounts to make sure they are all the same three-quarter inch tall.
This way you will know whether any of them are sagged as well, contributing to the unequal height issue.

Broncos lean for all sorts of reasons. All the usual ones that could affect any vehicle, as well as the radius arm affect.
There is also the unfortunate issue of inconsistent manufacturing. Have you had this bronco long? Has it always had the lean?
Don’t forget to measure and compare everything pertinent to this test. Leaf spring hanger locations, front coil spring towers and lower mounts, trackbar mount location, etc.

Is there a suspension lift installed already?
Along those lines, and important to this test, are they the original rubber C-bushings, or have they been replaced with polyurethane?

 

[BGBronco]

I chased Bronco lean in my 1976 as a solo garage job several times and it turned out to be a combo of worn-out bushings and body mounts that were (obviously) in bad condition. Not specific to your question but I waited too long to take care of what now consider to be baseline things. New bushings, body mounts, getting the caster numbers in range, and magically fixing the lean along the way.

 

[ba123]

I checked my level on frame stands and then looked after mounting the front axle, but I think it's more important to just be sure your front axle is even and right so you can rule that out.

If you disconnect the axle and leave the radius arms on, it's easy to tell.

If you lay them on the ground, still attached, they should both touch the ground. You can also use jack stands that are set to the same height, which is what I did as I didn't want the ends on the ground.