3/4 ton suspension

[Duro5341]

Hey guys, I have a 86 K10, LWB

My bosses dad, offered me a 85 K10, SWB for free......the body, and frame are pretty bad apparently

Now he says he swaped over the 3/4 ton suspension, it has a 350 4 bolt, and he thinks a 3 spd auto.....

Now I want the axles for sure, to get them rebuilt with 3.43's, and put them into my truck.

My question is, will the 3/4ton leaf springs swap over the my truck? or will it require some finess....

The truck is located about 1.5hrs from my shop, and i'll have to rent a truck, and trailer to get it down here....so around $300-$400 max. As my rear end backlash is screwed, and makes one hell of a resonence in the truck, and it only has 2.86, and won't tow worth ****

Just wondering if this truck is worth getting, or should I just walk away?

Duro

[69BBsuburban]

The axles/springs "should" swap right over......although I believe there are two different length rear springs.....52" and 56"????

[Prerunner1982]

as far as I know should be a bolt in ordeal. May need a different u-joint.. may not... but truck to truck should bolt right in. I dont know if the cost of the rental truck and trailer is worth the cost of the axles.. but if you can sell the engine/trans/tcase it would definately be worth or if you have a need for them.. Just for the axles I dunno..

[Prerunner1982]

Originally Posted by 69BBsuburban

The axles/springs "should" swap right over......although I believe there are two different length rear springs.....52" and 56"????

The 1/2 tons could still have had the 56"s. I dont know for sure about the 4wds, but the 2wds came with either. Even if the good truck has 52"s the swap is easy since the holes are already in the frame for the 56" springs.

[MylilBowTie]

Would both spring perch's move farther apart for a 56in setup from a 52in? Just wondering how it would be down with keeping everything in correct alignment.

[Zilverado]

I did a similar swap/upgrade of rear axle and springs from a '77 "heavy-half" (8-stack leaf) to my '86 1/2 ton. It required a relocation of the rear spring hanger and shackles. As Prerunner mentioned, the holes already exist in the frame. I just had to drill/cut the factory rivets to remove the rear hanger, and simply bolted the hanger back in, in the new (further back) location. The hanger at the front end of the leaf springs remains in the same location. Then the heavier rearend and springs bolted right in.

I did have to go to a cross-over u-joint - the cup sizes on the drive shaft yoke were different than the pinion yoke. Readily available part, and reasonably cheap. Just go to the parts store with your measurements, 'cause it's not something they can look up in their "U-joint" book under "Chevy"...

Have fun.

[Zilverado]

Originally Posted by MylilBowTie

Would both spring perch's move farther apart for a 56in setup from a 52in? Just wondering how it would be down with keeping everything in correct alignment.

In my case (and I believe this is typical) only the rear hangers moved back. In other words the distance between the front hanger and the axle is the same in both set-ups. It's the distance between the axle and the rear hanger that increases. In this way, the rear-end geometry (drive shaft, pinion, differential and axle) remains the same. Except for a slight change in pinion/u-joint angle caused by the lifting effect of the longer, stiffer springs - at least in my case.

[Duro5341]

They both have a 10 bolt rear end, so I am not worried about the u-joints, they just swapped in the 3/4ton leafs (more stacked up)

I think my 86K10 is the 56" leafs, but I will measure to be sure.....just getting things organized with people who have 3/4ton, 1 ton trucks, and trailers to pull this to waterloo

Duro

[Duro5341]

Well I didn't measure it, but my truck I am 99% sure has the 52" leafs. When I look at the frame it looks like the rear shackle can move back about 2-4" and there are another set of hole that look the same as the rivits in the current shackle

I am planing on moving the truck back to waterloo in the next month, and then the work starts

Duro