Truck: 1991 F150 running 89F250 rear leaves and a sky shackle flip.

My rear end does not flex for beans. No doubt it is the F250 pack, and possibly the 90* shackle angle. Compression and droop are both **** poor. Shocks are not limiting travel. I am assuming removing the over load leaf, or possibly the next one up would help flatten the spring pack a bit making the truck sit level, and help the tire stuff? And maybe even keep it from bouncing on freeway transitions? What about opening up the spring clips from a C shape to a U shape to help them droop?

How it used to stuff with the sway bar even.(old pic, like 3 years ago)


Max stuffage right now.

 

man is that box twisted! i would go ahead and open up the spring clamps. as for as the overloads go, i would only remove them if you never load the truck. not sure what to tell you about the leaf ttb front end, I have been trying to figure out how to get the front of my bronco to flex without lifting it to extreme heights.

 

The front is coils and actually flexes better than I figured it would, fully cycles 10'' travel shocks at least. Since I joined the Coast Guard the truck is really more of a toy for cruising around town and light wheeling when I make it up to the mountains. I think its days of slogging through the woods packed full of green oak are over with for a while...

 

Ditch the overloads. These are designed to add resistance when the spring flattens out. This is the opposite effect you are looking for.
Do you have a pic of that shackle angle when the vehicle is at rest? The wrong shackle angle will make the truck ride rough and will kill suspension travel.
If you have a sway bar, you will have to get rid of that too.
Longer springs can help a ton, and you wont have to compromise weight carrying capacities. I still tow a car hauler with my other 1 ton on 44's behind my red truck, and mine flexes like a toyota. I have the best of both worlds after I installed stock 64 inch rear springs from a 3500 series silverado.
For not a lot of money, you can have some real crazy flex and fix the problems that you currently have.

 

I agree with 75350, ditch the overload springs, and look for longer springs. Here's the flex my truck has now that she's got her big girl shoes on. She's an '87 F150, but the only thing original anymore and half ton rated is the frame and axles. This is what the 5.5" superflex kit from Bronco Graveyard got me.....even with the stock radius arms. You can get a whole lot more flex with extended radius arms.




This is the stock spring pack (right) vs. the new pack (left). More leaves means that less leaf has to hold more weight, which makes it more flexible, which makes more flex. And its got a real nice ride to boot!

 

Nighthawk: Your truck looks good, I would recommend the long radius arms! My truck stuffs the tires all the way in the wheel wells, and drops out farther than yours does! Here is the pick of the shackle angle... And you can see my spring pack, I would be removing the lowest spring.

 

There is your problem right there. That hanger is bolted in the wrong place. See thae angle prevents the spring from forming a larger "U" shape. The shackle would have to pivot forward, and it is just out of length. It cant swing any more than an onch or so, and the suspension is limited.
Now consider what has to happen when the spring flattens out. It has to move the shackle backwards, and since it is so far forward already it has to raise the back of the truck to get the shackle past the over center position. The weight of the truck itself is preventing this.
This entire thing is all wrong. Forgive my verbage, but I cant sugar coat it. You will have to move the hanger forward.
You should use a magnetic angle finder to determine the current angle, and then determine where the upper pivot would have to be to achieve a more desireable rear angle. Once this is achieved you can plumb a line to set the upper pivot, and mark the holes in the frame with the use of the hanger itself. Drill new holes, and you will be done in one shot.
Fix this, and you will get far more flex than you have now. Forced articulation cant take place, and the entire suspension is limited because of the poor shackle angle.

 

Thats what I needed to know. I was all ready pretty sure of that, just wanted to make sure 100% before drilling more holes. What would be a better angle to shoot for?

 

There is no magic formula really and this has as much to do with the length of the shackle as it does with the amount of flex the spring is capable of. You will undoubtedly have to lean the shackle towards the rear of the vehicle, and this cant be so far that when the spring compresses it does not over ceneter the shackle causing it to smack up against the frame and get stuck. Yes this can happen. This is why the style of hanger you have has a stop designed into it. Longer shackles can change this and offer more flex of the spring. The spring will change length as it cycles and the shackle has to be long enough to permit the spring end to move and the kength to change. If the shackle cant swing or pivot enough, you leave travel and articulation on the table.
What I do is try several lengths, and cycle the suspension to achieve max flex without compromising strength or promoting side sway. Yes this can be real time consuming, but it is what is needed to get the ultimate in travel. Been two years and I am still working out the little bugs. I can get a mean stuff though, and when it extends it looks like something is broken it can flex so far. This is with a spring that can still haul some serious weight. I have hauled over 2,000 Lbs in the bed, and have hauled a trailer that had a net over 10K lbs. Same springs. (3500 silverado, bone stock leafs)

Get that shackle angle back around 30 degrees for that stock spring and you should find a cnight and day difference. Again, there is not a set angle since every sring reacts differently and the shackle length has as much to do with the final movement as anything.
DId I lose you yet?????

 

No it makes all kinds of sense. It also why the truck likes to almost hop when both rear wheels hit the a same bump, the spring is pushing against the shackle until it moves past the vertical plane. The only thing I am not looking forward to is getting those nuts started with out pulling the gas tank. That was the hardest part the first time. I should be able to get this done next week, I have to get my jack stands back from my brother this weekend. Thanks a million, I will keep you updated.

 

Here is a pic of my shackle angle, i made mine longer too... maybe this will help ya.(pay no attention to the stacked lift blocks)

I also basically have my rear springs turned around.. it moved my rear axle back by about 7.5 inches due to the axle center pin not really being center on the springs.. so with the axle closer to the shackle the axle will move farther so more wheel travel...

(the big traction bar fixes the prob the stacked blocks would have caused)
here is what i did to the spring, prob not the best way to do it, but its been like that for over a year without any problems. just redrilled the one main leaf, and turned the rest of them around.

 

Thats a nice long shackle. Could it over center upon full compression?
Looks like it will droooooop like crazy.

 

I tried to make it so the shackle will almost bind on the spring at full compression.
A picture is worth a 1000 words. lol

this pic its kinda hard to see the shackle angle on the side thats compressed, but helps show the flex. thats my friend standin there. right about 6 foot tall.