Anybody done this? While working on the brakes of the F3 I found the drivers side main leaf broken. I have an F-1 for pieces and the leafs look fine. They appear to be the same size width wise just a little thinner. How many leafes are in a leaf pack from the factory? Might be a good time to remove a few while changing the leafs over to the other truck. The F-1 springs have three redeeming qualities

1. They are paid for
2. They are not broken
3. They probably would give a better ride including height the are thinner. It looks like it would drop the front of the truck about an 1".

 

my guess is that they are thinner because they are designed to be a softer spring they wouldnt hold the same weight as the f3 spring would

 

Just an opinion, but wouldn't the full leaf pack from the F-1 be about the same as removing every other leaf from the F-3 springs? The only problem I can see is that the suspension on an F-3 is set up for the factory springs so you might have some susp. travel issues, but I don't know.

 

I have F-1 springs on my '51 M-3. They bolted on without a problem. They are basically identical but drop the front end like 1-1.5". I was in the same problem as you since one of the M-3 springs was broken and didn't match the other. You only lose like 500 lbs capacity in the front. I also use the rear springs also but this requires relocating spring hangers. I made a template from the F-1 frame and drilled new holes in the M-3 frame. I also took the rear spring hangers from the F-1 which bolted right on. I kept the entire spring pack together because the 8 foot box weighs in at 500 lbs! which is alot heavier than the F-1 box. I did submit a tech article on installing F-1 springs and rearend in a F-2/3 and M-3. In my gallery 1st '51 Mercury M-3 shows the frame.

 

That is good to know. From what I could tell everything in the front would bolt up. I hadn't got to the rear yet like to do I thing at a time.
What was difference in the rear springpack and hangers location?

 

The F-1 spring is 1" shorter and 1/4" thinner. The spring shackle mounts under the spring mount. You will need new U bolts.