I have an 85 F-150 ext cab 4x4. I want to swap the stock ifs with a solid coil sprung unit out of a late 70 150 or bronco. If any one has done this or has any info on the subject please reply/ Thanks!

 

I have never done this on a 150, but from what i've seen, you will have to relocate the trailing arm mounts. So, now would be a good time to put your lift in. You will also need the lift to clear the axle. There is another thread around here that deals with this. I am doing the same on an 84 F-250, with a straight axle from a 77 F-250. It's a lot of work, but worth it to me.

Jared

 

Here's a little info:

https://www.ford-trucks.com/articles/axle.php

 

Boy, I hope the guy in the letter got his gear ratios matched up. There is a few 80's trucks riding around here w/ solid axles so, it seems to be one of the "things to do".

 

I am currently doing this to my 84' f-150. Heres the thing. I didnt want to spend $2000.00 on the kit they sell at bronco graveyard.
So i have been doing using stock equipment. The problems started with
the frame width. 80-96 frames are wider than the 73-79 frames so i turned the original radius arm brackets opposite....left side to right and right to left. This turns them inward so that they will
mate with the radius arms. This seems to work Ok. Of course you need to remove all the IFS components. The old ifs spring buckets will not
work so you will have to remove them too. If you are going to use a
lift kit you can get the solid axel under the truck without a problem
but if you use the stock springs the crossmember will hit the diff
housing. I cut some material off of mine and i think it would be wise
anyway since offroad spring compression could still possibly cause contact. Then all you have to do is measure from a point on your
rear axel to your front until you match both sides. Getting it centered in the fender wells is not that hard. Then once front to back alignment is done measure and get your axel centered side to side
What i did was take the main tie rod off my ifs. I cut it slightly
sleaved it and rewelded. It has a adjuster at one end which allowed me to move it where i needed it for the pittman arm. Originally i wanted to use the 79' tie rod but it wont fit the pittman and the 79'
pittman wont fit the 80's steering box splines. So its just gotta be
a custom job. You will need the 70's style spring buckets(4x4).
Once the frontend is where you want it attach the springs and then
slide your spring buckets close to where you think they will line up. Now what i did was i had a big air jack in front of the truck so i could raise and lower the front of the truck at will. So gently
apply pressure to the springs while they are centered in the buckets.
The buckets will have a lip on the bottom which will help keep them
on the frame. I used welding clamps to hold them solid until i got them where i wanted. I also used the spring retainers on the top of the buckets. This can be dangerous. Gotta be careful. So once you apply the pressure and like how things are lining up, raise the front
of the truck remove the springs and drill the new holes. They are 7/16
The rivets holes are 7/16". One thing to remember is that nothing will just line up. I dont think one hole on this entire project has.
Measure measure measure. Okay now comes the hard part........
its the dreaded TRACK BAR. This is where i still havent decied what to do. I have it temporalily mounted to a piece of flat bar steel and
mounted under the steering box. I still havent decided what i want to here. As a final note the brake lines will bolt to the 70's calipers if you take driver side to passenger and vice versa.
Hope this helps. If you have Questions just ask. Eric

 

Hey Ford_SIX (or whomever else wants to take a shot)

On the F250 i'm assuming you are moving from the IFS arms & I-beams to leaf springs in the front. How do you know where to put the blocks to hold the springs? Are there holes in the IFS frames?

Don't know if you have a 4x4 or a 2x4. I know the IFS 4x4's already have leafs up front, but I keep seeing threads about the 2x4s being converted...

 

250 and 350 4x2's used coils. As far as locating the springs, since mine already had leaves, it is easy. I don't believe you can use leaves on an F-150, as the front of the frame has a crumple zone.
Send me a note if you need more info.

Jared