How can I tell if my font leaf springs are worn?

[derotoreut]

Hi all. I am new to the 4X4 forum. I just bought a '70 K10 SWB fleet side to go along with my '69 C20 LWB. I have been searching the site trying to find out if my front leafs are worn and sagging. From what I've read, it seems as though a lot of them are almost flat with little or no arch. On mine there is some negative arch to the front springs and there is only about 1-1/4" from the top of the springs to where it would hit the rubber frame bumper. Seems like maybe they have worn and there is not enough lift, but I'm not sure. Maybe this has worn and sagged over the years. Can someone shed some light here please?

[Stocker]

Very nice looking truck, congratulations! Can't give a definite answer but I'll mention this: when I replaced the sagging front springs on my K20, I measured 7/8" to the bump stops, and it was bottoming out easily. The new 2.5" springs resulted in a 3.75" gap.

Subtract 2.5" (my lift springs) from 3.75" (gap) gives 1.25", or what the nominal gap might be for stock springs in good condition. Maybe you don't have much sag after all.

[derotoreut]

Makes sense. Anyone else have any information on this?

[CrewCab59]

All stock front spring 1/2,3/4 69-72 and the newer 1/2,3/4 and 1 ton 73-91 are flat to negative. Stock came with 2 and 3 leaf spring packs. The aftermarket springs always have a poly or rubber bushing on the outside to make up the difference to the hanger. The stock spring is almost as wide as the hanger.

My 71 CST blazer has 3 leafs 1.5 from bump to spring plate.

My 71 GMC SWB has 2 leafs 1.25 from bump to spring plate.

[derotoreut]

Originally Posted by CrewCab59

All stock front spring 1/2,3/4 69-72 and the newer 1/2,3/4 and 1 ton 73-91 are flat to negative. Stock came with 2 and 3 leaf spring packs. The aftermarket springs always have a poly or rubber bushing on the outside to make up the difference to the hanger. The stock spring is almost as wide as the hanger.

My 71 CST blazer has 3 leafs 1.5 from bump to spring plate.

My 71 GMC SWB has 2 leafs 1.25 from bump to spring plate.

Great info. Were the 3-spring packs on K20's? My K10 has 2-springs. Are your springs original or did you change them out?

[CrewCab59]

Originally Posted by derotoreut

Great info. Were the 3-spring packs on K20's? My K10 has 2-springs. Are your springs original or did you change them out?

Both my K20 Burb and Brush truck are 3 leaf and all stock. The blazer was a 2 owner, hasn't been touched.

The other option is install a full add a leaf , we installed those on trucks with 7' and 8' snow plows they were setting level with no rake.

The 73 and up were mixed 1/2 and 3/4 could have 2 or 3. All 1 tons were 3 leaf.

[RANDY COX]

Sag,Sag,Sag,seems like after some years they all sag somewhat,my 77 cj-7 was bottoming out just normal driving hitting a small pot hole,the rubber snubber was also missing,had it been there it would have literally been riding on that,so without it,it was hitting the metal pad.Metal on metal not cool,So I installed a shackle lift on front and solved that problem...

[Stocker]

Originally Posted by derotoreut

Great info. Were the 3-spring packs on K20's?

The OEM springs that were on my K20 were 2 leaves per side. May have been a difference between standard or HD suspension, I don't know, but mine is a light-duty (6800# GVWR) K20.

[burnin oil]

atleast on the 73+ models 2 springs was standard and you got the 3 spring pack with the trailer or snow plow option. I just replaced the springs under my 72 K20 and used the cheap lift from JC Whitney on the front. Got new springs(front) and 4 shocks for $300. That was a rough country 4" lift. Alot on here say it rides bad but honestly it was an improvement on my ride. They have a smaller lift available also. I like the 4" personally. A little taller but not enough to look like you are questioning your manhood. Yes that was a joke! The biggest improvement to ride quality was replacing the rear springs. Rides better and let me ditch the lift blocks that were in the rear. Face it 40 year old springs are worn.

[derotoreut]

I am thinking that I may just end up changing out the front and rear springs. I have no idea if they are the original installed leaf springs or not. I want to keep the truck stock, as it is right now, but I would like a small lift. I am thinking of something like a skyjacker 2.5" lift, but I don't want to have to change out steering components too. Any thoughts are appreciated.

[Stocker]

Originally Posted by derotoreut

I am thinking of something like a skyjacker 2.5" lift, but I don't want to have to change out steering components too. Any thoughts are appreciated.

My K20 has Skyjacker 2.5" front springs that I installed several years ago. No steering components needed changing, and the brake lines were plenty long enough. All you need to change is the front shocks b/c stock ones are too short. I took all the compression / extension measurements -- stock rear shocks are a perfect fit on the front with 2.5" springs.

[69GWC]

Yeap thats what skyjacker set me was rear shocks for the front.
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