Hi all, I have a '79 F350 "trailer special" or "camper special" (spare tire is in side of bed). 8900 GVWR

The truck "sags" about 1/2 inch on the passenger side. It looks like a large part of the sag comes from the passenger side rear leaf spring. I have already put some spring boosters in the passenger front coil spring and while that seemed to help, it didn't fix the overall sag , which I think it coming from a weak leaf in the rear. I know for sure since I once carried a large load of rock in the bed, and that side of the truck did sag - and I also measured from spring to frame (unloaded), and on the passenger side, the spring is closer to the frame (in the center of the spring) making me believe its sagging / weak a bit.

A question I had was - I notice is when I jack the rear up by the pumpkin (differential), as the truck goes up, the passenger side of the axle droops DOWN more than the driver's side does. In other words, as I am jacking the rear up, the passenger side tire comes off the ground LAST and the axle basically sits at an angle, leaning downward on the passenger side. That seems strange to me if it was a weak passenger spring? Or does that make sense, if the spring is weak would that mean it would also droop more too (the other direction)? I would have though a strong spring would "push down" harder and make the tire come off the ground later. But in my case the left tire comes off the ground earlier, while the right comes off last. And the right side is where I see sag when the truck is on the ground normally.

I am pretty sure the problem is that rear passenger leaf spring is worn out / weak.

Anyway, I was looking for a way to boost the spring with a leaf helper, but the basic ones don't fit, the spring is too thick (7 leaf). And the guy at the auto parts store said they really don't have 1 Ton truck leaf helpers ever for sale there. I am not sure they even make them.

Other than going to a large truck shop and having new leafs put in, any other options I may have ? I just want to level the rear of the truck out. I myself notice the sag and it bothers me.

 

You could simply buy replacement springs from any online retailer that makes OEM replacements.

I think my last ones came from truckspring.com or something similar.

 

And local spring companies (if you have one in your area) can even do what they call re-arching the springs for you. But personally now that the existing leaves are forty years old, and with the cost of labor being what it is these days, I'd be more tempted to replace with new than ever before.

Of course, you can always shore up the existing ones with something like air-bags or the like, but unless you set it up so you can adjust the bags individually, you're still fighting a weak side.
Same for just adding a spacer in the amount of the sag. That will get you sitting level when the bed is empty but won't do much for the additional sag under load.

I'd say a new set of springs is your best bet.

Paul

 

Mines doing this too, about 2 inches lower on the driver's side. Has been time for new springs for about 5 years now. I just tell everyone I couldn't decide whether I wanted the ever-important, milennial-spec "leveling kit" or not, so I just did one side. 😁 Rough country springs and shocks going on come spring time. Throw my spare tire and a cinder block on the strong side for now to keep it copaesthetic.

 

The “cheap” way to fix this would be to take both leafs off and take them apart then put them back together but swap every other leaf... this would even out the springs.

Id buy new springs but if $ is tight this might get the truck back to level.