Have a 92 f250, would like to put a dually rearend and springs under it.
Will the springs fit? What years?

 

I think the dually springs are skinnier than the 250 and 350 single rear wheel springs (something like 2.5" vs 3", not sure exactly). Not sure how to solve that problem other than removing the leaf spring mounts from the frame by grinding off the rivets and bolting on the dually spring mounts in thier place. Spring length should be the same. You could also use the springs on your truck with the dually axle to simplify installation, but you won't be getting the increased spring rate to go along with the heavier axle.

Also note that using the dually axle in your F250 does not legally increase your GVWR to that of the dually.

Make sure you get that axle form a pickup truck and not a chassis-cab, as the chassis-cabs have skinnier frames and thus different spring and shock mount positions. In '92 the dually F350's I think were using Dana 70 axles.

You need an axle from a truck that has an electronic speedo in it, so the axle will have the VSS (vehicle speed sensor) in it so your electronic speedo and rear ABS will work. There is a little sensor on top of the axle housing above where the pinion comes out, with a wire attatched to it. Not sure when they started with the VSS in F350's but my '92 single rear wheel axle (10.25" Ford) has it. Your axle should be the same as mine if your GVWR is 8600 lbs or more.

If your truck is 4wd the gear ratio in the new axle must be the same as that in the old axle, or very close (4.10 vs 4.11 is fine).

The driveshaft and pinion yokes on the dually should be Spicer 1350 series. I think the F250 is the the same but not totally sure. If it's not, your shaft may need to be rebuilt with the different yoke.

Pinion angle may be an issue and depending on if your truck is 4wd or 2wd and how long the wheelbase is and what kind of truck the dually axle came out of will determine if you need a wedge shaped shim under the springs or not.

You should be safe choosing an axle from a '92-'97 truck. Other years may fit, but those are your best bet.

 

Thanks DesertRider, that helped alot. My truck is 2wd and I go down to the local stone quarry often. It does good with handling the load, but want a little bit more.

 

You can get adapters from arrowcraft to put dual wheels with your current axle. This won't add weight capacity, but it will increase stability. You could then couple it with helper springs or airbags.