Measuring suspension lift for new c bushings

[russhow73]

So that previous owner had done some work on the suspension.
I installed a 2" body lift, and need to install new c bushings.
I have no idea what suspension lift height they did, does measuring the springs give the suspension lift height?
I want to make sure and get the correct degree c bushings.

Thanks as always

 

[Thunder Chicken]

Pictures W/ TIRE DIMINSIONS would help...also there is a measurement you can do from the frame to the ground that will give you the approximate amount of lift

I'm wanting to say that 7 inches from cross member to floor was stock but I really can't remember ...someone on here will chime in I'm sure

 

[tobinj]

Taken from another thread.

measure from the top of the axle tube to the bottom of the frame. Stock measurement is about 7in for the front 6 in for the back. anything above those numbers can be considered your lift.

 

[russhow73]

Just found this

Yep, the general rule-of-thumb used to be 1.5° per inch of lift, then it changed to 2° per inch. But by that time we were also realizing that most (almost every one?) Broncos had not been delivered with the called-for caster reading in the first place, so it got to the point where even with 7° bushings and only 2 to 4 inches of lift, we were finding we had a LOT LESS than desirable caster readings.
The book calls for (differs by year) from about 2.75° to 4.25° of "positive" caster. Most of us (me included) have less than the minimum even with the big bushings.
So yeah, unless you know exactly what you have, more is better. So just go big.
The only trade-off is that, the more positive caster you give it, your pinion angle goes down farther from optimal too. So far though, up to the point you're talking about, it's been a reasonable trade-off. For those with extreme cases though, like where the bushings still aren't enough to get what they want, they have to cut the outer yokes off and rotate them to achieve the desired caster. I wouldn't worry too much about that until you get it measured, but at least now you know what sometimes has to be done to get it perfect. If you come in at anything over 2° positive though, it should drive pretty well.

 

[DirtDonk]

That long-winded answer sounds vaguely familiar... ;D

I want to make sure and get the correct degree c bushings.

Measuring for suspension lift is a good idea. But if your Bronco is driving right now, I'd go to the extra trouble of taking it to an alignment shop and having them give you a printout of your readings so that you have a reference point.
Usually doesn't cost much if they're not taking the time to adjust anything, so it's a good small investment.

The real issue here though, becomes determining what c-bushings are on there now. If they're already the big ones, you're not going to get more caster easily.
If they're smaller though, you'll know what you need to do when you find out what your caster is currently.
If they're rubber without shoulders, you're at zero offset. If they're poly with shoulders though, hopefully you can find out from either looking at them from the side (hard to do) or taking them off to see if there is still a number on them.

Good luck.

Paul