Front end is probably a 72-5, was originally drum brake
Then it's a safe bet that you will want the 7 degree bushings even with a 2.5" lift. Not that they're an absolute necessity, as Rustrytruck mentioned some Broncos drive really well on minimum caster. My '71 also has just barely 2 degres (1.75° on one side) and drives like a dream.
But not all do...
There are a few that have decent caster from the factory, but those are flukes rather than the norm. It was not until '76 that we started to see better caster angles from the factory. And even then, not all had enough caster and needed more bushing or some modifications.
The problem already mentioned is not all EB front ends can handle the 7 degree bushings without getting very near their travel limit with the front u-joint. Most are fine, but here again, not everyone is so lucky. That's why it's nice to know what the caster is before deciding which bushings.
I wouldn't think it would be necessary to cut/rotate the C's for a 2.5" lift, I have been wrong before though..
In most cases, probably not. But it is sometimes, and is still really the only way to get good caster numbers and maintain a good pinion/u-joint angle.
Not a big deal on the street, but some still get put in 4wd now and then.
Can you explain? Never heard of this and curious. I have a 77 with manual steering and also considering 2.5-3.5" lift
Because you have a '77 it's a good bet that your caster is decent and you can keep it down to a 4 degree bushing. But it's really good to know where you're starting from, so maybe sometime before you do the lift you can get it on an alignment rack and get a printout to work from.
Some shops will only charge a minimum since all you want is a readout and maybe a toe-in adjustment if needed. But definitely get the printout on paper. If their printer is not working then get a screen shot so you have a reference point.
Then you can choose which bushings to use.
But the whole "cutting-n-turning" thing is when you are able to rotate the steering yokes (or "outer C's" as most call them nowadays) so you can keep the u-joint angle at a minimum near the factory setting, and dial-in the exact amount of caster you want with no limit.
It's more work, but not as bad as it sounds at first. The weld holding the yoke casting on to the end of the axle tube is ground off, the yoke turned, then re-welded in place.
The "steering yoke" is the bit at the very end of the tube that the ball joints on the knuckles attach to, and where the assembly actually pivots when steering.
When these things were built originally they all had manual steering until '73 and more positive caster makes it harder to steer. So they not only used the minimum specified by Ford, but it seems like they often got away with even less. Back then nobody noticed with small bias-ply tires, stock suspension heights and manual steering. They handled about as well as a person back then would have expected a utility truck to handle.
Nowadays we have different expectations and just can't leave well enough alone sometimes!;D
Paul
