Radius arm drop bracket question

[MrT]

I just put in Duff's 3.5" progressive coils and my springs are bowed. I also put in 7 degree C bushings from WH. This is all on a 1978 F150 axle. There is no body or engine so they are tall right now. I have a lot of caster and it just doesn't look right. Do I need drop brackets or is there something else going on? I know they will sit a couple inches lower with some weight on them. If I need drop brackets do I need to go to 4 degree bushings?

Pics:
Passenger side.

Driver side.

The caster.

 

[Broncobowsher]

You are looking at an illusion due to no weight. Measure the axle to frame gap and it is several inches of drop to get to your desired ride height. Once it is loaded everything will look better.

 

[needsmoarturbo]

Yeah. Wait til the engine and body are back on the frame. Right now its too soon to tell what your caster is going to be at and how bowed the springs will be. They should straighten out some as they compress with weight on the frame..
The last photo shows camber, not caster. Which is corrected with ball joint shims if necessary.

 

[MrT]

Yes camber, I am getting my butt kicked today. The threads under the coil plates were messed up and I had a drum that refused to come off. I got them both done but nothing is ever easy.
I will keep going and see how the coils look later.

Thanks

 

[DirtDonk]

You may never get all the bow out unless you tilt the radius arms, or add tapered shims under the coil buckets. And even then might not.
You'll never really know for sure until the trackbar is connected and the suspension is compressed to ride height.

Is the axle still full-width? Did you widen the coil buckets the exact amount? Looks like the spring pads are wider spaced than the spring towers. With the lift you get forward bow. With the wider spaced lower mounts/cups/buckets you get inward twist.
Any misalignment of the coil mounts is going to impart at least some bow in one direction or another.
In many cases the axle will not sit square beneath the frame with the trackbar disconnected. It can shift from one side to the other just from the coil spring pressures, or any slight skewing of the radius arm brackets, or spring clamps.

You can find your final bow by compressing the suspension down to approx. 10.5" from the top of the front axle tube to the bottom of the frame rail. If you want to get it all equal, the rear can get compressed down to 9.5" between the axle tube and frame rail.
This is the approx. height with a 3.5" suspension lift.
Adding weight is problematic sometimes (unless you can push down on it with a forklift or something!) but compressing things with ratchet straps has worked well for many here over the years.

But as said, you may still have some bow. It's something that we've been dealing with since there were lifted radius-arm Fords. Orienting the lower spring cups square and plumb with the upper spring towers is the only way to minimize it to the lowest level.

Paul

 

[MrT]

Thanks for the information. The axles are full width (+6") I used Duff's offset buckets(+4") they look lined up pretty good head on. There is a new thread asking for compressed height with these springs. It looks like they will come down from 21" now to around 16.5" after. That will change things a lot for the better.
I do gave a question about the plates the coils sit on. Are they supposed to be flat? Mine have bends in them, they look the same on both sides but definately not flat.

The frame to axle is 15" now.

 

[DirtDonk]

The aftermarket spring cups are usually flat, but the factory ones are stamped steel to better form to the lower coil of the spring and let it sit more naturally.
One of the ways this is compensated for slightly with the aftermarket flat ones is by leaving the area that holds the coil in more loose. This lets the coil flex a little more.

The stock ones can also settle over time, forming over the top of the radius arm after many years and miles of bouncing around with a couple thousand pounds of Bronco on them.
So it can be hard to tell even in pictures if any are still in good shape or partially collapsed. If they've settled quite a bit though, someone with known good ones could probably compare to some good close up shots of yours.

Paul

 

[Nothing Special]

As was mentioned already, the picture you showed shows your camber which isn't affected by the lift or by drop radius arms. But caster is, and it's important.

When I bought my Bronco it had ~3" lift. It actually drove pretty well, but when I tried to flat tow it the steering went the wrong way. Turned out I had negative caster. I tried 7 degree C-bushings which brought me close to zero caster, but I still couldn't flat tow it. So I added radius arm drop brackets and was able to get the caster into spec (I don't remember what C-bushings i ended up with).

Based on my limited experience I'd say you probably will not have your caster in spec without doing something (drop radius arms, long arms, cut and turn). But will you need to get your caster n spec? As I said, my Bronco drove great, even with negative caster. It shouldn't have, but it did. So like others are saying, I'd say wait until you get it back together and see what you think then.

I will say that I really wish I'd have done something other than the drop radius arms to fix my caster problem. I do use my Bronco off-road and it doesn't flex well and it catches the radius arm mounts on rocks a LOT. At the time it wasn't in my budget, but I wish i'd have gone with long arms. As it is now, I'm tentatively planning on a project for next winter to improve my articulation and especially my ground clearance. (This picture sort of shows what I have now).

 

[661buster1963]

Does anyone make shims for coil spring buckets or would a guy need to fabricate them?

 

[DirtDonk]

Used to be able to get them from Ron at Sierra Broncos, but I don't think he's been around for a long time.

Might be something available off-the-shelf from one of those custom metal fab companies (think Ruff Stuff Specialties and the like) but not sure.

Paul