Referencing my post from the middle of April (original post here) I have decided to replace my rear leaf springs. I have come to this conclusion because I have had my camper (30 foot travel trailer @ 8K lbs) out the past 2 weekends and the wheel hop is especially bad with the trailer in tow. There is a considerable amount of sag with the trailer hooked up and a WD hitch, more than I would expect, so I have decided that the leaf springs must go.

With that said, I have a few questions.

1. Should I swap out the factory F250 springs (4/1) for F350 springs (6/1) and will they fit as a direct replacement bolt on.

F250 springs here - 99-04 Ford F250, F350 Rear Leaf Spring - 5 leaves, 3000 lbs

F350 springs here - Ford Rear Heavy Duty Leaf Spring F250SD, F350SD - 7 Leafs, 4400lbs. | $169.95

2. What are the torque specs for the eye bolts and U-bolts for the rear leaf springs?

3. Should I replace the rear shocks bolted to the axle tube while I am at it or wait to see if my wheel hop issue is fixed after the leaf springs are replaced?

4. Can I do the swap in my garage or should I have a mechanic shop do the install? Any advice or lessons learned on getting the new springs mounted is appreciated.

This will be the first time I have done any work on leaf springs, so I am a bit apprehensive. I plan to swap everything on the rear leaf springs except for the hangers which appear to be riveted into the frame. I will be swapping springs, shackles, bushings, U-bolts and eye bolts. Although I consider myself a pretty decent shade tree mechanic and can normally figure my way through just about anything.

Thanks for any help/advice you can provide. I am prepping the truck for a 7,000 mile trip with the trailer in tow at the end of June and want to make sure it is in top shape.

 

I did mine recently and it's not a bad job to do. You'll need to jack it up pretty high and support it with something. I used logs on end under the frame back near the bumper. ATS Springs won me over. They can tell you what you need. I don't know about shipping though.

 

Hunter, thanks for the recommendation of ATS, they are a few dollars cheaper than SD linked above it seems. Do you happen to have any of the torque numbers or did you just crank down on the bolts?

 

I confess to just cranking them down. I reused some of the large bolts if they weren't worn. The Ford frame nuts have wings on them so they won't spin and I liked that feature...no wrench needed on that nut.

 

Torque specs for U bolts are based on the diameter of the bolt shank. Lots of published charts on those, including from manufacturer. They are (technically) a one time use only part, due to rolled threads instead of cut. Be sure to retorque in the first few hundred miles after installation. Loose u bolts means broken springs.

 

Retorquing is well advised and I do need to get out there and give them a crank.

Another thing I learned is that when you attach that rear shackle to back end of the spring before hoisting the spring into place with your groin, some grunt and some knuckle skin make sure you have the head of that shackle bolt facing the frame rail. If you have the nut pointing that way you risk having the bolt sticking out raking across your frame back there. Yes, there is a reason they have that bolt in there so you can't get it out.

I can't stress enough how high you have to have the truck jacked up to do this job. You will either need a jack with one heck of a travel to the ram or do as I did and have two bottle jacks so you can step the rear down enough to do the job after you support the frame way up high.

 

I was looking at the SD and ATS site and they both list specific torque specs for their kits. I did not know this was the case, so once I decide on a kit I will get the specs from the retailer.

As for lifting the truck, I have two jacks, 4 stands and plenty of wood to stack so I feel I will be able to get the truck high enough. Only time will tell though. I suppose if I cannot get it high enough I will be forced to pay a shop to install them for me.

 

If you have jacks, blocks and jack stands you should be OK. I had a pair of jackstands but they weren't tall enough. I have a woodpile with some stuff that's about 24" long and a 4x4 on top of that at the rear of the truck. That means you should need about 28" of support if you are at the rear. With jackstands you might be able to support the frame ahead of the springs. You don't want to get in a situation where you have the truck supported, springs unbolted and don't have enough clearance to drop the rear far enough to do the job. Those springs flex quite a bit under the load of just the truck and you'll need to account for that. And don't forget that the jack will still be under the rear and that will eat up some of your space. I also had to drop my tail pipe to get the right side spring back in because the tail pipe hanger was in the way.

And make damn sure you block those front wheels so it doesn't roll out on you. I put mine in 4x4 as well to help with that.

 

All very good points. Did you have to remove the shocks at all to drop the axle far enough to remove the springs? Did you have any problems breaking the axle loose of the springs when attempting remove the leaf pack?

I am at a camping site right now hanging out and just crawled under the truck to have a close look and to verify that there is zero rust. So, I am grateful and hopeful that the bolts will not be welded to the nuts by rust.

 

Yea I'm looking at doing mine also since I how 6 days a week. This was a question I had also. Been talking to sd springs and they just needed my spring number and they could recommend a heavier duty spring to help with towing. Will be ordering parts shortly for mine.

 

I hear ya, as you read earlier I have a 7,000 mile trip planned at the end of June with a travel trailer in tow, so I will ordering a set this week. Not sure yet if I will go with ATS or SD yet, it will come down to total price with shipping as the part numbers and prices are nearly the same.

Are you getting wheel hop or axle wrap or is the rear of the truck sagging a bit when a load in on it?

Hoping to get some more feedback on what this job entails as I only want to order parts and do the dirty work once.

 

Little wheel hop when going around turns, but it sags a lot when I hook up. Can't expect much less with 15 year old springs. I had big plans for this truck, but I'm pushing this one over to being my full time work truck more and more instead of playtoy.

Basically since it will styy hooked up from this point on, the suspension is getting some slight tweaking. Doing new rears from a 350 most likely for better load weight, switching to One Up Off-road rear 4-5 inch single block instead of the stacked now. Also ditching the 1 inch hanger front kit and 2.5 leveling kit and going to a solid 4 inch front spring. Bushings will be updated, shocks also, and trying to line out what I'll be using for brakes. Most likely EBC drilled and slotted rotors and green pads since I'm sticking with 16 inch wheels. If I went to my 20's I have here I would haven't went for bigger brakes, but seeing as I am making it a work truck, why waste that money on tires that big.

 

I didn't have any trouble removing any bolts but I had recently had a lift kit removed by a garage so the U-bolts were new. I reused them. Even the big bolts that hold the springs in the shackles came out easily. I did soak them all with Liquid Wrench for a week before I did the job. I do believe I unbolted the shocks from the rear to permit the drop. One other thing to keep in mind...the new springs will have more arch to them than the ones you remove so if you barely have enough room to get the old ones out the new ones won't go in and you'll have to drop the rear more. And it can be tough to not bang the paint up on the truck while you're wrestling that spring into place.

 

Wheel hop? Why are you spinning your tires with a trailer?

 

I am not spinning my tires when pulling a trailer. I am not spinning my tires at all, but I am getting axle wrap/wheel hop due to what I think is my rear leaf springs being old and worn.

I hope this clears things up a bit.