I am looking into replacing the rear leafs on my truck. Driver side is sagging. The spring shop says that the leaf for my truck is an "odd ball" size, code C-7. However, he has two listings for those odd ball leaves and one has a higher arch than the other. How can I find out which were used on my truck. The spring shop guy suggested I call ford and have them decode the VIN. I was going to jack up the truck, take the weight off the axles and measure the arch that way but this would actually cause the axle to pull down on the leaf and give it more arch. Hoping someone has some suggestions.

By the way, the spring shop guy suggests I replace the leaves and the shop I usually deal with sais they can re-ark the old ones. I would just as soon replace them with new ones. They go for around $200 CAD each.

Thanks

Guy

'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, LT235/75/15 Tires.

 

Don't re-arch, it won't hold the arch for as long as new, although it may be cheaper up-front. If you have the choice, go with the "lighter" spring packs if you don't haul much or really don't load it up often. Go with the "heavier" springs if you do, might ask what the spring rate is, if they are different (and I think they will be), then you have something tangable to consider. This is expressed as how many kilo's per Cm? For us due south, lbs. per inch, the higher this number, the stiffer the spring will be with the opposite true for the lesser. So in other words it comes down to what you want (ride quality) and what you need (load capacity). I also beleive the spring shop would be best to help with this choice as this is what they do and can most likely explain things/options a little better. Nothin' against your regular guy though!

 

Thanks for the reply Chuck. I contacted Ford and got a part number from them which the spring guy then crossed referenced. My springs are 25"x32-1/2" with an 8-1/4" arch. Those are really expensive he says because they are uncommon. Special order too. He's got a 25"x32" with an 8-7/8" arch in stock for around $115 CAD each. Says the rear spring shackle should handle the 1/2 inch difference. I don't do much heavy hauling so I'm ok there. I'll just go with stock. I will ask though what the spring rate is for future reference. I'll be doing the change myself in a week or two. Spring shop said I should replace u-bolts too while I'm at it. The only part i'm not sure about when replacing the leaves is whether or not the axle can get misaligned during the swap? I've got a book on Ford truck chassis' and it should explain well enough. If I remember I'll try to post back here when I'm done.

Guy

'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, LT235/75/15 Tires.

 

 

Hey Guy, thanks for postin', always nice to find out if/what/when or how things work out! As far as the alignment of the axle, there will be pins or bolts thru the center of the springs, called simply enough, centering pins/bolts. I should have mentioned that one should always use new hardware including new centering pin/bolts, once you have removed the nuts from the u-bolts, it's strongly recommended you don't re-use them (more cost of course!). When doing this work, try to get your hands on some larger C-clamps (one will work, but I like to use two) and use these to hold the spring pack together while you do the actual removal and installation of the new, this will give you some measure of control and you will need to compress the center of the springs when installing, not so important when removing, but will help keep them from "flyin'" apart-they do have a lot of energy. You might want to soak everything down with PB Blaster or other penatrating oil a couple of times before hand to ease the nut/bolt removal. On another note, you might want to ask about teflon pads between the leaves, this helps them slide against one another and will give a slightly smoother ride, if they don't already have them that is. The reason I thought of this is the slightly shorter spring length, it may give a slightly "choppier" ride, general rule is the longer the spring the better the ride because it can flex more. The little bit of difference shouldn't make much difference but am thinking that the pads may compensate for this and then some. Good luck with your removal/installation, it's some bull work, but really pretty straight forward. Don't be to concerned if she rides high when you first install them, they will "settle" anywhere from 1/8" up to 1/4" or better after the truck has been on them for a while. One other thing I just thought of, you might ask about removing one leaf from each pack, not sure of your exact situation, but this can be done at the expense of load carring and some durability. It would lower the overall tail-high stance and would give a better, softer ride. Might be worth asking anyway. If I can grab anything else worthwhile or important rollin' around in the noggin', I'll post it for you!