First would be why I want to replace my rear springs. When I bought the truck the leafs had all been replaced so they are in good shape. That said, I have never owned a truck that rode as terrible as this one. I put super springs on the front with a drag link and cross over steering and that helped. Then I replaced the seat and that helped also but the rear end doesn't even feel like it moves. The only load I have had the helped was when I hauled a motor and transmission. I pulled my car trailer empty and it road worse. The weight of the trailer was too light and bumps the trailer hit could be felt in the truck. It was a jarring on highways. I assume this is because the springs were not doing much damping. I drove an 03 super duty as a daily for many years and never had a problem with ride so if I could get this truck comparable I would very happy.

Some of the springs I considered:

• 99-07 SD rear springs
  • Cheap for aftermarket pro comp lift springs.
  • Not sold on pro comp spring quality.
  • Most 99-07 SDs weigh more than my truck so I will give up ride quality.
  • Would be able to handle any load I would throw at it.
  • Finding good used ones is a challenge as the trucks are all older
• 08-20 SD leaf springs (18-20 are suppose to ride the best)
  • Can get a good used set for a decent price.
  • Springs are loooong which could add more fab work
  • Can handle any load I throw at them but I give up some ride as most SD are heavier than my truck.
  • Pro comp sells lift springs that are reasonable
• 09-14 f150 leaf springs
  • Long and soft
  • Finding good used ones can be hard
  • F150 weight and load rating pretty equivalent to my highboy
  • Wheel hope will probably be a problem
  • May need air bag if I have heavy loads
  • Can buy after market raptor springs if I want to burn some cash
• 15-20 f150 leaf spring
  • Main difference between these and the generation before is they are shorter on the forward fwd end.
  • Easier to get a low milage set used

So what did I get? I bought a set off a 2016 f150. I believe they are the lowest load rating of the f150s which is ok because I have decided ride is more important as I can add air springs to increase the load rating easily.



I set the truck on the springs to get an idea of lift block height I will need. I was a little nervous doing this and probably only had the springs compressed for a minute or less. This should be the equivalent of having 300-400 lbs in the bed over the axles.



I am thinking about add air springs with daystar cradles so the airbags won't cause a problem if I am off-roading.

​​​​​​Don't know when I am going to have a chance to get started but hopefully will be done by spring. I think I could have it done in a couple weekends if I don't run into any problems but I doubt that will happen.

 

Cool project. Can't wait to see how it progresses. Hopefully you won't run into any stumbling blocks, but well, you know how that can go sometimes.

Clever idea to compress the springs under the truck. No way you're going to hurt them that I can think of. Other than the weight of the axle and tires, that's the load they're going to be carrying the rest of their life anyway. And you can easily load more in the bed than the weight of one axle and a pair of tires.
If you're rarely going to carry anything, you could even hold off on the bags. But I'd do the same thing as you're planning, and do it all at once while you have the tools out and the mindset to make things work. Can't hurt to have the additional capacity at your disposal for that time when you decide to offer your services to carry fire wood home from the hinterlands!

Can't wait to see the next update.

Paul

 

I think those springs will be a good fit for your application. Todays 1/2 tons have hauling capacities of 70's 3/4 tons. What width are they? 2.5"?

Similar to the 63" cheby springs I put in mine. I used a 2+1 leaf which was lightest option, and just happened to be what I could find easy. Can easily gets 3+1, 4+1 for cheap or high quality high leaf count lift springs.

Do you have axle wrap and wheel hop issues now?

 

thanks! I will not haul or tow that often but it would be nice to have capacity when I do.

They are 3" wide. There is a 3+1 f150 spring but that's about it and super duty springs are a little longer so they won't bolt on in place of f150 springs. I had already purchased the hangers thinking I was doing super duty springs so going to Chevy springs was ruled out. I had a set of 2019 f450 springs and realized my truck was way to light and never going to haul that much so I sold them.

I have noticed a little wheel hop sometimes. I assumed long soft springs could give me trouble so I got a traction bar kit from ruff stuff when they had a sale.

 

Made a little progress on this. The rear dana 60 is a posi that will only spin one wheel and has a lot of backlash. The hub seals also leak gear lube even though they have a speedi sleeve on the hubs and I have replaced the seal multiple times.

I was considering a 14 bolt but could not find one with less than 200k for a decent price. My old jeep has a dana 60 rear out of a dodge that was rebuilt with a detroit locker making spending money on a 14 bolt hard.

​​​​​​So I pulled the dana 60 out of the jeep. It is only a 30 spline so it really was not tough enough if I ever do put the j10 back together.



checked the guts to make sure everything inside was still good.


I have a lot of garb to cut off the diff but using the 60 should allow the rear driveshaft length to stay the same.

 

Now that is good recycling!

 

Made some progress.
I got the spring hangers mounted. I got spring mount measurements from my neighbor's truck to verify the f150 builders pdfs were acute. Between the f150 builder pdf and the f250 dim pdfs I was able to align the new spring hangers pretty easily.
I did have to clearance the bed support for the shackle to clear.



lift blocks ended up taller than I expected. I was planning on a 4" and ended up with 6-1/2" so the u-bolts I ordered were too short. I also had to offset the the lift block 1/2" to move the diff forward since the springs are more angled than the old ones. The bump stops worked out pretty well. I was able to bolt on some super duty bump stops I had and fit a piece of pipe for the stop. I have it set up for 3" of up travel plus whatever the stop gives.




​​​​​​

 

Nice work. Surprised you needed that tall of a block. Guessing old frame is flatter than the 150 and front hanger is up higher?

Block height won't matter with 'Ruff traction bar. It will change anti-squat properties but you can likely make it quite flat to minimize lift under throttle.

 

With that much block too, I'd probably be using 5/8" u-bolts if you're not already? Looks like you have the thickness in the top plate necessary to handle the torque on a big u-bolt (in the 140lbs and higher range) and with that much length I'd sure be using the largest diameter u-bolts available.

As smoky diesel brought up the traction bar, using a traction device like that would also lower the stress on the bolts I would think? Not really sure, but it feels to me like that would be the case.

Paul

 

Definitely using 5/8 u-bolts. I will add tabs on the rear end to keep the u-bolts from moving. When I first got the truck it had the huge stack of leaf springs, stock 4" block with a 1-1/2" bolt stacked on it and overloads so the u-bolts we're crazy long. Somewhere around 18" or more. So even with the tall blocks I think they are not as long as the original u-bolts.

I also already have the kit to build a track bar and an air bag load assist kit. I have toyed with the idea of removing 1 to 1-1/2" out of the lift blocks and adding the height back with pressure in the air bags. I think I should drive it at the current spring rate before I add more spring rate to it though.

 

Made some more progress this weekend. I hope to have the truck on the road by Saturday. I probably won't get the track bar done but it should be drivable at least.

F150 mounts the shocks on the outside of the springs so in tried to overkill the mounts since the shock has so much leverage on the mount. Keeping the shocks inside the frame was going to get tight with the track bar and moving them farther out on the rearend should increase there effectiveness. The f150 shocks also have a lot more travel than the original shocks. The shock angle is about 30 degrees.

Ran out of welding wire which slowed me down.



Building shock mounts



Shock mount and shock mounted on frame.

Air bags mounted to frame. I still need to get the lower air bag mounts done but I ran out of welding wire.

 

Nice job on the outboard mounts.
How close does tire come to the shock body?

 

I am also interested in how it fits. I like your detail on the mounts, very good job!

 

What air bag do you go with and what is it's travel range?

 

I would do your lift blocks like these, Looks like a good idea.
https://www.pmfsuspension.com/Ford-F...ocks_p_42.html

Sorry I didn't see you were going to add tabs for the ubolts.