The Stovebolt Site Forums The Shop Area The HiPo Shop Leaf springs versus 4 bar kit

If you aren't familiar with the background of my plight, the PO decided to try to lower the truck on the cheap by flipping the axle. I've tried nearly every set up I can think of since then with the latest being running the leaves over the top of the axles like they're supposed to be ran. Having only a floor jack and some jack stands, I had it up as far as possible and was still needing another 6" of lift before I was going to be able to get the driver's side leaf put back on. I decided to play Superman and try to bend the leaf down. It went a few inches down.

Time for new springs!!?!? I'd say!! Maybe this is why even with air shocks, I can't seem to get the frame off of the axle.

So now I'm looking at springs. And finding some 4 bar set ups as well. With a price difference of $20 cheaper for leaf springs shipped, I'm thinking the 4 bar is the way to go. Plus as this will be my daily driver, I'm thinking that the ride will be improved.

Has anyone here done one? Suggestions? Precautions?

Sorry if this is in the wrong forum, but as it isn't a "stock" set up, I figured there'd be more people in this one that may have done this upgrade already.

I was looking into a 4-link (4-bar, same thing) setup for a different project at one time, and a rod shop that sets up tons of them told me to go with a triangulated 4-link instead of the parallel setup. This is because the triangulated setup is much easier to get the angles right, and adjustments can get you back in line if it isn't 100% square. The parallel setup is supposed to be much more finicky.

I would check your prices though, as when I was looking, the cost of the kit plus the coilovers would be much more than the cost of new leafs. However, if you want the adjustability in both ride height and quality, the 4-link is the way to go.

Another note on axle flips, there is nothing wrong with them if they're done correctly, but they can give a very severe drop. You might find that with new springs that the ride height and quality is fine. What year is your truck? Have you checked a local junk yard for used springs?

There's a guy about 30 minutes away from me that had done one on his AD truck, but I'm having issues finding his name, number and address. I do remember his biggest bit of advice to me was not to cut the frame. He stressed that to me several times. And not to do the S-10 swap. Said it wasn't worth the time.

I found a 4 parallel link setup for $589 before shipping and the cheapest leaves I've found have been right at (model 2799 heavy duty) $530 shipped. There's a local spring shop here in OKC (formerly known as City Springs, is now Fleet Pride) that I am going to try and swing by this Saturday to see if they have anything that will help.

Anyhow, I'm working on a 52 3600 with a heavy rear end

I was able to get some others off of a 52 or 53 3/4 ton GMC. I put both on and am still bottoming out. The air shocks won't bring the rear end up at all when aired up and the frame weight put on them. If there are some other springs that will fit this old girl and give her booty a boost, I'd be willing to keep the springs.

I figure that with new(er) springs, the axle flip would work fine. And I really like the stance and height that the truck sits at, but both sets of springs I have currently don't have enough life left in them. Not surprising considering that they're 60 years old and have hauled so much weight during their service lives.

I swapped the original rear for a Camero 10 bolt and TCI spring kit. I don't plan on racing and the price helped make the decision.

What year did you use?

The 10 bolt is a 1980 but I believe several years earlier and later will work as well.

Aaaaannnndddd...It's back! LOL! This thread disappeared on me earlier.

Spring shop should be able to rearch your springs or add leafs at a very reasonable cost.

That must be a heavy truck or really worn out springs! My '37 had nine leafs in the rear stack (1.75" wide) and was so stiff it would not bounce, even with original worn out springs. I removed 4 leafs and added teflon liner just to get it to move.

Are you sure the springs you have are for a truck?

How about a leaf spring set up using coil over shocks. The leafs hold the axle in place and the coil overs hold the weight. All it would require is a good solid mounted crossmember on top.

Joe

I obviously have a different opinion on the S-10 swap, but you can see those opinions in my other posts in other threads.

Keep in mind that with the 4-link kit you also need to buy coilovers. Those will likely run you $350-500 as well, so your 4-link could be twice the price.

That's what I was about to mention as well, but the ad says they're included. I've been trying to decide between a four link & springs too and thats the best price I've seen.

Make sure you're looking at the right springs though. The model number you listed was for a 3100, they won't fit your 3600.

@Joe H: I replaced the ones that came with the truck. Had all of 4 leaves in them. The ones I bought came off of a 50's model GMC 3/4 ton. There were 8 or 9 leves in the main stack and another stack that are reinforcements. Without a 3' long U bolt setup, I haven't tried putting the reinforcements on to see if that would make it work. I'm almost ready to see if I can find some just out of morbid curiosity at this point. I haven't priced any coil overs yet, but it sounds like they are almost as expensive as buying the 4 link, so unless I can find another deal.... Off to search I go!

@46gmcpu: From what I've seen, some of the S10 swaps are done to perfection. But I don't have the money or skill to do it, so I'll have to save up to do it on another truck. Do me a favor and don't tell my wife I'm looking for another one, OK?

@mobileortho: I'm finding that looking for anything to do with this old 3600 is like finding a needle in a 160 acre hayfield. If you buy two of the 4 link setups, I'll send you my address

Delta,
If you are going with anything other than stock running gear you will probably find you'll be doing a bit of custom fabrication. While most anything you will need for your Bolt you can find at many vendors, it is mostly built for the 3100 not the 3600. A good example would be the rear rear sway bar where you will need to use your knuckle buster skills to get it installed.

True enough. I'm still learning the welding stuff, so I'm not too afraid to try something new. This has caused me to look at every weld I come across to see how mine compare. I'm certainly not afraid of the "beat it to fit, paint it to match" mentality. However, if there's a right way, I'd like to try it first so I don't spin my wheels or throw money away.

You're right, I hadn't noticed the link to the ad before. If that's the true price with coilovers, that's a decent deal. I would still go with the triangulated setup though.

i went with the bolt in kit with the optional sway bar....installation couldnt have been simpler...plus the upper shock mount really helped with the mount for my fuel cell.. bolt in kit ... installed .........dave

It's really not to bad, I have one myself. There is actually alot of the 3100 stuff that will swap over but it gets kinda tricky when it comes to some of the suspension components. The rear springs on 3600s mount on top or the axle, the 3100 mounts beneath. If you want to use the 3100 springs check out another member here, BIG CHEVY 3600. He swapped them on his truck.

If you're interested click on This

@BIG CHEVY 3600: Were those springs for the 3100? Do you happen to know where you got them?

I got them from TCI. It is a bolt on install
And: TCI-2

Well, I may have found yet another solution. I found an air bag that should fit right over the axle and bolt into the frame. It won't have a compressor initially, but I could add one after the front drop spindles nd disc brakes are installed. Options are kicking my butt right now.

you can always do a little measureing and head to the local salvage yard. once you have the measurements you need you can walk around the yard and measure up some and compare. you would be surprized if you didnt find exactly what your looking for. as for the tci kit i used it and it was pretty much a bolt in other then having to drill a few holes. the only thing i added was a backing plate on the front spring mounts because of a rust issue behind the original front spring bracket. i am sure you could use the 3100 setup on the 3600 with just a little research in the assembly manual and a tape measure. i got my kit off ebay farely cheap and every thing was included. as far as a four link suspension i was told from a local rodder that used a four link in one of his rods that he didnt like them because of the tendancy of the rear axle to steer through corners. i really apreciate this guys words of wisdom because of the work he does with his cars. which have all been award winning and he actually drives them about 10,000 miles a year.

The only difference between the 3600 and the 3100 is the 3100 frame width is a little over 11" wider than the 3600 which makes installation of sway bars necessary to do a little fabrication.
While the front suspension is heaver on the 3600 the frame width up front is identical to the 3100 and not an issue in upgrading to IFS.