I have a Canadian made 1997 F-150 4X4 with a broken leaf spring. The spring code on the tag is 4D. I cannot locate a reference for that code anywhere, and none of the junk yards in my town can find it on their lists either. I did find a code "4" and also a code "D" but not "4D". Both the "4" code and the "D" code reference a 5560 spring. Can anybody tell me what springs I can interchange with "4D" ?? I need to find one soon, have to tow my boat next week. I know I can buy new, but will have to buy a pair and it's about 350 bucks - trying to find a used one and save some money here. Here's a link to the door tag codes, my 4D is not in the rear spring section. Thanx!
http://www.fordf150.net/howto/decode.php

 

4 is the front code and D is the rear code. The D code for 97-98 is a 3 leaf (2/1) system rated at 1375 lbs per side. If you need to go a little heavier duty now would be the time to do it and you can reference new springs here http://www.generalspringkc.com/index...parent=78&pg=1

 

Hey Joe, thanks so much, that totally makes sense!!
One thing, I don't see 1325 pound capacity rating in the link you provided, but I do see 1180 (mine - I measured the pack thickness) and 1415 spring capacity. If I upgrade to 1415, or whatever the next size up is, will the rear of the truck ride higher, or will I have same ride height, just stiffer springs? Don't wanna look like a stink bug!!
Thanks again

 

The ride height will be pretty close because your D code has a free arch of 9-1/4" while the 1415 lbs capacity spring has a free arch of 8-9/16". Now the heavier spring is a little thicker on the pack thickness and obviously stronger which makes up for the free arch difference so overall the ride height should be very similar and take you back to stock height and maybe a little higher but I would say no more than 1"

 

Great! I think I may want to opt for the upgrade. So, when calling around for the next stronger capacity set - will it be a different code, or still be a D code, with a different different capacity? I know the vendors are gonna ask for a code, just want to be sure I have all the info I need when I start calling again. Thanx again

 

The 1415 lbs capacity spring has a couple of codes you could use to get that particular spring. So I'll give you a run down and when I put 2004 that is the heritage version of the truck or basically the 97-03 style and not the 04-08 style because in 04 the springs switched to 3" wide with 2 center bolts.

A Code = 2004
H Code = 1997 - 2004
J Code = 1997 - 2004
N Code = 1997 - 2004 (Except 1998)
P Code = 1997 - 1998