[updated:LAST EDITED ON 16-Nov-02 AT 02:56 PM (EST)]Ok, so we are all pretty much in agreement that mono leaves up front is generally a bad idea. However, what about in the rear?

For the new 9" rearend, I am thinking about running an Air Bag over Leaf type of setup. My leaves are pretty much shot and I'd need to get new ones. To achieve the amount of drop I want in the back, roughly 3", I'd have to probably remove two leaves. Or, I can save all the hassle and get a 3" dropped mono leave.

Thoughts and/or suggestions?

- JT

 

One thing I found out is you don't want a weak spring pack, and then compensate with an airshock or air bag. The springs have to remain somewhat strong to properly locate the rear axle. If they get too weak from taking leaves out, it can cause the nose of the diff to move up and down causing driveshaft angle problems. And also if you ever get down on the gas pedal, wheel hop from mushy springs can be a problem. The air bags sound good just to keep the ride height level when hauling something heavy.

 

[updated:LAST EDITED ON 17-Nov-02 AT 10:25 AM (EST)]Franklin,

Since you brought it up, just how many leaves do you think can be taken out safely? My F-3 has 13 on each side, and I was thinking I could maybe cut it down to 6. How much lowering would be accomplished by taking 7 springs out? I don't plan to use the truck to haul anything really heavy and I doubt if I will ever get down on it hard enough to cause wheel hop. Also, should I just take every other one out, or does it matter which ones you take out?


JT,

I've heard the monos give a great ride, but the're a little too expensive for my old truck especially when there's nothing wrong with the ones I have (except it rides like a brick).

 

> Since you brought it up, just how many leaves do you think
>can be taken out safely? My F-3 has 13 on each side, and I
>was thinking I could maybe cut it down to 6. How much
>lowering would be accomplished by taking 7 springs out? I
>don't plan to use the truck to haul anything really heavy
>and I doubt if I will ever get down on it hard enough to
>cause wheel hop. Also, should I just take every other one
>out, or does it matter which ones you take out?

JT,

One way to get some sort of estimate is to look at an F-2 or F-250 and see the range of spring packs available for those lighter trucks. The shop manual gives the available options for all truck sizes for a given year. You probably have very little extra weight on the rear springs from the F-3 truck itself - the extra spring capacity built into the F-3 springs is mostly for the extra load carrying capacity. If an F-2 or F-250 can get by with 7 x 2" x 1/4" leaf packs on each side you may be able to use a similar setup on your F-3 as long as you keep your bed loads down. I would think spring windup from the axle torque would be similar to the F-2 or F-250 although, in the lowest gears, some of the F-3 or F-350 rear axles may have high enough ratios to think about.

Franklin, I'd love to hear your take on this.

 

George and Earl. I have an F-250, I believe Franklin is the one with an F-3.

My F-250 is currently equipped with 9 leaves in the rear. I'd like to remove 2 or 3 leaves and add airbags in an air over leaf arrangement to help compensate when I am ever hauling everything (rarely).

I talked with Air Technologies and they don't recommend mono springs for their air over leaf systems.

Comments by brian@ridetech.com (Brian Shaw) at 11/18/02 10:11am

"If you use a mono leaf there is no way to lower the truck further when you take air out of the bag. I would do a multi leaf, when you take leafs out it softens the rear so it will drop when the bag is deflated."


- JT

 

Sorry for the mixup JT - Vern has the F-3 and I'm not sure what Dave Franklin has. My 1956 shop manual lists three different rear spring packs for the F-250:

standard - 9 leaves with 1950 lb capacity - 2.25" wide leaves
optional - 11 leaves with 2400 lb capacity - 2.25" wide leaves
optional - 12 leaves with 2800 lb capacity - 2.25" wide leaves

Sounds like you've got the smallest packs already with just 9 leaves - same as my 1956 F-250.

For the 1956 F-100, the shop manual lists:

standard - 7 leaves with 1050 lb capacity - 2.00" wide leaves
optional - 8 leaves with 1350 lb capacity - 2.00" wide leaves
optional - 9 leaves with 1750 lb capacity - 2.00" wide leaves
optional - 9 leaves with 1250 lb capacity - 2.00" wide leaves

That last one looks like a typo maybe??? Could that be 2150 lb capacity??? At any rate, if you are willing to live with a load capacity around 1000 lb you could try to come close to the smallest F-100 spring packs. That might be around 6 leaves at 2.25" width instead of the 7 leaves at 2.00" width standard on the F-100. If you're going to take out three leaves maybe you should leave the two outer leaves and take out three alternating leaves from the remaining seven on your F-250 packs. You might also get by with just five leaves - keep the outers and take out every other leaf between. Another option I've read about someplace would be to reverse the lower three or four leaves. They become inactive until the load gets high enough to bend the upper leaves a little in the reverse direction so they contact the reversed lower leaves. This is all just guestimating of course.

One other point, if you don't have a shop manual this quick and dirty estimate shows just how useful they can be - even if you're not going strictly stock! Get one from the online store if you don't have one already. Best bucks you'll spend on your truck and you'll be helping to keep this place going for us to enjoy.

 

Thanks George. My 1953 shop manual list the same figures, even right down to that weird 9 spring with the lower load capactiy.. weird, I don't think it's a typo.

- JT