What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Is there a difference in 1/2 ton and 3/4 ton rear springs?

WJACKSON11X

WJACKSON11X

1/2 ton status
Joined
Mar 12, 2007
Posts
754
Reaction score
15
Location
Madison,GA
I have a 91 Suburban that I put a 3" TC lift on recently. Front springs and rear blocks. It still sits low in the back due to worn out rear springs I believe. It also rides very soft in the rear. I was thinking that maybe I could swap some junkyard springs that would give a little more lift and maybe a stiffer ride in the rear. Would a set of 3/4 ton springs help at all? Is there a difference? I heard an add a leaf will make it ride rough. Here is a pic of the saggy arse. It probably sits about an inch low in the rear. I'm worried about pulling my small utility trailer with golfcart and boat with it.

 
Yep, likely shot springs.

Two options really. Smooth ride with lighter duty springs, or harsh ride with heavier duty springs when unloaded.

Likely there were about 15 different rear springs used on these trucks from the factory depending on pickup, K5, Suburban, tank size, day of the week it was made, etc.

Proper way to determine spring requirement is to know the weight that will be on the springs under worst case conditions and buy springs with the proper rate so that you don't exceed that number.

Add a leaf did seem to make mine ride a bit harsher vs. stock springs, but it's such a subjective "measurement", who knows. It brought the rear up, so there is obviously more resistance to compression, which means it had to get stiffer, but by how much is anyones call.
 
I figured there was no rhyme or reason on which springs are in what vehicle. I need to measure and see what length springs are in it. Im not too concerned with a stiff ride in the rear. I thought about ordering some lift springs, but figured some junkyard springs would be cheaper if I could find a set that would help out.
 
I would assume that even wrecking yard springs will be worn out to some extent, but that would be completely dependent on load you will subject them to whether they will be ok for your app or not.

There is definitely a rhyme/reason to why GM used the springs they did, all based on GVWR. The light 3/4's would have a different spring than the heavy 3/4's, and again probably different springs among those choices based on body style. Doesn't take long before you end up with a multitude of part numbers that way.

Someone else will have to comment on spring length, I figured the 1/2 and 3/4's were the same but I could be wrong. At this stage of my life I will just buy new springs that are the rate I need, in the hopes it doesn't ride like a dump truck. Add a leafs ended up raising the rear more than the front in my case, likely due to worn front springs. But I don't tow anything with more than about 300lbs of tongue weight either.
 
It was pretty common for K5's and 1/2 ton Burbs to sit low in the rear even when new. If you installed fresh 3" lift springs in the front along with 3" blocks in the rear I would fully expect it to still sit low in the rear. Along with this most off the shelf lift kits were designed for pickups which almost always sit high in the rear. From my experience you usually need more total lift in the rear of a K5 or 1/2 ton Burb to make it sit level as compared to a pickup.

An add-a-leaf doesn't make the ride worse just because it's an add-a-leaf....it has the same effect if you put stiffer springs on it. Basically installing a stiffer spring pack or an add-a-leaf into the existing pack are essentially the same thing. One good option is to get a pack out of the junkyard and play around with combining leafs from the old and new pack to get it right. Requires some work though.
 
Took my spring packs apart and added two of the longer leaves from a separate pack, raised it pretty level and firmed up the ride back there quite a bit. Not harsh, still bounces over bumps, not like a dump truck, but obviously not like a Caddy either.





 
Last edited:
4xcrazy said:
Took my spring packs apart and added two of the longer leaves from a separate pack, raised it pretty level and firmed up the ride back there quite a bit. Not harsh, still bounces over bumps, not like a dump truck, but obviously not like a Caddy either.





Click to expand...

Dumb question maybe. what do you do about the clamp that holds the pack together. My spare set of 52's looks like I can remove it but on the Burb pack it doesnt.
 
I cut the tab off that wraps around the top leaf, leaving the upright portions, I was wheelin it quite a bit while I lived in Arizona, rocks and such so I left them the way they are to help fan out more for more drop. It hasn't caused any problems at all like that either, with any sort of driving or towing. I don't believe I have even messed with the springs since I did that about 6-7 years ago now.
 
from what I have read burbs could have 52" or 56" in the rear .

measure first then count the # of leafs you have . the bottom overload is always a given . if you have 4 and a over load they will be listed as 4+1 pack and so on .

then the thickness of the leafs and the main leaf dictates the pack weight spec along with the # of leafs .

used by this time is going to be whipped and shot unless you can tell there newer replacments .

these 2 places have good info/prices .

info = http://www.stengelbros.net/Chevrolet-GMC-Truck-Leaf-Springs_c_191.html

pricing = http://www.sdtrucksprings.com/

my k30 1ton I am redoing I am using 22-547 packs @ 2600lbs per pack . lightest 56" spring offered . then I am adding firestone air bag kit rated to 5K lbs extra capacity . this will get me a smooth ride and when needed air up bags for the capacity back .

if you can get few good pics of the springs you have now and post up we can help you figure them out real close .

get the ubolt center area and then the ends of the leafs .

if you were closer I got some 22-617hd with overloads on top I would sell ya . . . ha ha ha 4650 lbs per pack with out extra overload on top .
 
sweetk30 said:
from what I have read burbs could have 52" or 56" in the rear .

measure first then count the # of leafs you have . the bottom overload is always a given . if you have 4 and a over load they will be listed as 4+1 pack and so on .

then the thickness of the leafs and the main leaf dictates the pack weight spec along with the # of leafs .

used by this time is going to be whipped and shot unless you can tell there newer replacments .

these 2 places have good info/prices .

info = http://www.stengelbros.net/Chevrolet-GMC-Truck-Leaf-Springs_c_191.html

pricing = http://www.sdtrucksprings.com/

my k30 1ton I am redoing I am using 22-547 packs @ 2600lbs per pack . lightest 56" spring offered . then I am adding firestone air bag kit rated to 5K lbs extra capacity . this will get me a smooth ride and when needed air up bags for the capacity back .

if you can get few good pics of the springs you have now and post up we can help you figure them out real close .

get the ubolt center area and then the ends of the leafs .

if you were closer I got some 22-617hd with overloads on top I would sell ya . . . ha ha ha 4650 lbs per pack with out extra overload on top .
Click to expand...

I measured the spring pack and indeed have the 56" springs, which sucks since my extra set are 52's.
they are 4+1 and have almost no arc to them. I'll see what I can find at the local yard.
 
"my k30 1ton I am redoing I am using 22-547 packs @ 2600lbs per pack . lightest 56" spring offered . then I am adding firestone air bag kit rated to 5K lbs extra capacity . this will get me a smooth ride and when needed air up bags for the capacity back . "

I looked at those springs (22-547). It looks like that is a 8/1 spring pack? That seems like a little much. Maybe not though. If mine came with 4/1, how come they don't offer one with less leafs?
I forgot to measure, but is the center pin offset on the 56's?
 
WJACKSON11X said:
I forgot to measure, but is the center pin offset on the 56's?
Click to expand...

Yes, a factory GM 56" spring pack has an offset center pin. From the factory it is 26" front spring eye to center pin and 30" center pin to rear spring eye. This is so all model trucks could use the same front spring hanger and then just move the rear hanger if it had 52" (which are centered) or the 56" pack.
 
6.2Blazer said:
Yes, a factory GM 56" spring pack has an offset center pin. From the factory it is 26" front spring eye to center pin and 30" center pin to rear spring eye. This is so all model trucks could use the same front spring hanger and then just move the rear hanger if it had 52" (which are centered) or the 56" pack.
Click to expand...

Thanks for that info:waytogo:
 
lots of light oem is not offered in aftermarket as most sales upgrade .

they ride nice in my stubby j.r. truck now as short as it is on 35" tires .

could always pull a leaf or 2 from the bottom .
 
Could I use a leaf or two out of the 52 spring pack or is that not a good idea? I'm having trouble finding 56 springs at a yard. I wouldn't mind just buying an add a leaf kit, but I'm not sure how much it would lift or help my situation. Don't want to spend a $100 to find out its not what I wanted.
 
you could but make sure you add them in so there layered out like stock .


and add-a-leafs tend to make the spring super stiff and hard ride . but they do lift .
 
sweetk30 said:
you could but make sure you add them in so there layered out like stock .


and add-a-leafs tend to make the spring super stiff and hard ride . but they do lift .
Click to expand...

I may try to add a few leafs from my 52 pack then. Thanks!
 
I have done lots of lift kits / add a leafs / heavy spring upgrade packs .

but never 1 time did I have anyone complain about the air bags .

BEST BANG FOR THE BUCK !!!!

I just got my own set for my stubby j.r. build . and amazon was cheapest at that time by almost 45 bucks. :eek1:
 
sweetk30 said:
I have done lots of lift kits / add a leafs / heavy spring upgrade packs .

but never 1 time did I have anyone complain about the air bags .

BEST BANG FOR THE BUCK !!!!

I just got my own set for my stubby j.r. build . and amazon was cheapest at that time by almost 45 bucks. :eek1:
Click to expand...

Great. Thanks for making me spend more money. Haha
 
You must log in or register to reply here.

Latest Posts

Top Bottom