Hi all. I have a 74 quadra van. It used a 2 trailing arm system with two additional diagonal arms going from the body straight down to the axle ends. It allowed articulation but zero up travel of the axle. Hitting a speed bump straight on was brutal. I had this converted to 3 link with a track bar to locate the axle side to side. I had a 4x shop do the work which they have failed miserably. After a year and 5k the best they can say is they can't figure out springs. What they installed are 4" lift jeep coil springs. These are very soft and do not come close to holding the weight of the van. The axle is sitting 1.5" below the bump stop and is hitting them so hard it's breaking the welds. So my question is, as the Jeep coil ends fit, is there an f-150 20" long spring that will be higher load rated. I know some have the 90 deg. Coil wire end to retain them. Do all f-150 coil springs have this for retention?
I crawled under tonight and looked up inside the coil cup ( top of spring) there are two bare studs sticking down about 5/8" apart. Could this be for retaining the coils that have the 90 deg ends?

 

I would weld in mounts and convert to a king coil over thats adjustable. It's hard to engineer and guess a spring rate. The good thing is make product for your issue. The downside is cost. Need to shop around hard. Get your driveline angles mint. And find a shop who you trust with premium parts. Icon might have options. You're looking at a pretty large bill but it's the final boss. Hopefully someone chimes in with budget options.

https://accutuneoffroad.com/product/...SABEgK9Q_D_BwE

 

I had trouble with my front springs being too soft, hitting the bump stops all the time, etc. Went to a heavier Moog coil and airlift air bags inside the coils. gained about 1" of ride height, much better ride, articulation, and have some adjustability.

It doesn't hit the bump stops now, and corners better on the road.

 

I thought the quadra van had Bronco coils, the front axle came from one, I have the build sheet somewhere for those.