3/4 ton springs in 1/2 ton.

farmer boy

Well-known Member
I have a 1997 GMC sierra K1500 with a 6 lug 14 bolt rear. The current springs are worn out and sit on the axle with a 1/2 ton of feed on it. I found some leaf springs out of a 2000 nbs 2500. Eye to eye they measure 62.5 inches (not installed) and are 2.5" wide The springs on my truck are 2.5 wide and 63.5 inches(installed). Will these springs swap with each other? How much(if at all) will the truck go up. I wouldn't mind an inch or two but don't want any more than that. I don't want to be able to load more on. Just don't like the suspension to bottom out every time you put the trailer on it or put some feed it. Makes you a target for the MTO.
 
I can not say for sure on a truck that new but I have taken and built my own spring packs and in your case that is what I would do. Keep your one main spring then take springs from the 3/4 ton set and built to meet you needs. My 1980 heavy half ton has 8 springs on each side and stock it had 6 and I have double over loads plus shocks with over load springs on them and have the same type shocks up front but it is a 4X4 also
 
I did like old said and just added more springs to one of my older chevy. One other option is to put Timbrens on. They are a heavy rubber cushion that bolts on where the axle stop is. They don't touch when truck is empty so you still have the same ride, and when loaded they keep the truck from swaying. We have used them on three work trucks and seemed to hold up well. They are about 200 bucks though, but bolt on in a half hour.
 
putting on bigger springs for weight is OK, but remember that you still have a 1/2 ton rear/front-end under it, would the wheel bearings be able to carry that much more weight with-out wearing out sooner. and how about the braking system, will it stop the extra weight with the heavier springs...my thoughts/questions
 
I had a 1996 F-150 4x4. I replaced the rear springs from a light duty F-250 (1998). It was the best handeling and towing truck I ever had. Just remember like other said, the axle is still half-ton rated.
 
If you have these springs on hand, you can jack the truck until the weight just comes off the springs (tires start to lift) and set the 2500 spring next to the original on the axle. That should give you a good comparison to the difference in stance.

As for the springs being 1" shorter, it shouldn't matter because the rear shackle can swing. Your only concern will be the holes in the eyelets for the bushings.
 
They are shorter because they have more arch in them, unless you are measuring spring length and not distance in a straight line from the eyes. You have to jack the weight off the current springs or put weight on the newer ones to compare the straight-line measurement, which is the important one. Also run a straight line between the eyes and measure to the top of the spring pack where it clamps to the axle, that will give you the difference in ride height.

Your half ton springs should give you 1500 or so pounds of weight capacity anyhow, you'll find it may ride a little rougher, but be more stable, with the heavier springs.
 
Except for the one that I have now I have had to replace springs in every one of the 18 trucks that I have owned. They cost so little and swap in a short enough time that I couldn't see doing it myself.
 
Two 2500HD Duramaxes at work. Maybe 170K between them. 2 sets of springs, need a third, a set of injectors, and a front wheel bearing.
 

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