4x4 Suspension Questions

[bhammer]

Hi guys,

I am attempting my first 4x4 rebuild of a 72 GMC. Forgive my lack of knowledge but I don't know anything about 4x4 suspensions, drivetrain, etc. I've only restored 2wd trucks. So I am wondering about the leaf springs, I was told that it would be good to swap out the stock front springs with 52 inch leafs and put on a B-52 Kit from DIY4X.com. Anyone know about this? Why would it be beneficial to swap the front out with longer leafs? Also here is what I am wanting to do, I want to do a suspension lift on the truck but I only want like 2 inches of lift. I am not looking for anything drastic. I know you can put blocks in place that will lift it up but are they strong and reliable? This truck is going to be my daily driver and I also want to be able to do some towing with it. Is it possible to put bags or something in the rear so when I put a heavy load on it the back end won't sag down? Can anyone help out a 4x4 newbie and direct me in the best way. Money isn't an issue, I'd rather do it right the first time and spend the money to get a good suspension set up. Any feedback is greatly appreciated. Thanks

Brian

Here's a list of what I'm currently working on.

72 GMC 4x4 (current frame off rebuild)
72 Chevy LWB (396, 2wd) Daily Driver
71 Chevy 3/4 ton LWB, no motor or trans.

[dieseldawg142]

52's will give you more travel, & a bit smoother ride. if you throw 52's in, you prob wont have to lift it, they will usually give you 2-4" depending on what kind of shape the springs are, & what kind of bracket you use.
and STEEL blocks are totally fine. have a set of 3" blocks on my crew. truck weighs 7600 lbs empty, just over 10 with the camper on, & 14 000 with the quad trailer & camper. been running them for almost 10 yrs-zero issues
i also have a set of firestone airbags in it, cause i too hate that tail-dragger look when loaded or towing. if you do serious 4bying with airbags, use quick release hardware so you dont rip them apart if you get all twisted up

[LONGHAIR]

Short blocks (no more than 4") are ok in the back, but never use them in the front. It is not safe. There is a lot more side force against the front end, plus the fore and aft steering pressure on the axle. Plus, most blocks are tapered, this will screw up your caster and cause your truck to wander. Then you would be back here posting "help, my truck is all over the road"......we just saved you the trouble.

[dbash]

Originally Posted by LONGHAIR

Short blocks (no more than 4") are ok in the back, but never use them in the front. It is not safe. There is a lot more side force against the front end, plus the fore and aft steering pressure on the axle. Plus, most blocks are tapered, this will screw up your caster and cause your truck to wander. Then you would be back here posting "help, my truck is all over the road"......we just saved you the trouble.

Great advice here, personally I don't like blocks in the rear either. If your going to lift it some you may as well try for a better ride all around.

I recommend that you ditch the factory steering arm and invest in crossover steering if its a daily driver. Its a huge improvement over the old "bump steering"

Deaver springs will make you a pack.

ORD (Off Road Design) has everything you need for the crossover steering.

My lift is a strong four inches with 33" tires.

[dbash]

One more thought, I have seen a few posts one here stating that a two inch lift on a truck with 40 year old stock springs resulted in four inches of lift.

Tired springs, worn cab and bed mounts and worn bushings are suspected to be the other two inches of gain.

Something to keep in mind if you only want two inches over what you have now if your current setup is all stock.

[dieseldawg142]

Originally Posted by dbash

Great advice here, personally I don't like blocks in the rear either. If your going to lift it some you may as well try for a better ride all around.

if your haulin or towing, go with blocks. i know my 4500 lb per side stock packs won't act weird loaded down, nor squat nearly as much
i dont know why people say ride, a block does'nt change your ride, your still using stock components with a little bigger gap in them. unless their real expensive or custom made, lift springs have a hard time matching a stock spring for smoothness.
if you were jamming the throttle to the floorboard, i could maybe see some axle wrap, even when i'm fully loaded with no run on a 15 degree hill with heavy throttling, have'nt experienced it yet.
if it ever did, a simple antiwrap bar with spherical ends would take care of it
if you want better articulation, hard to beat a well designed spring though, & yeah, a big loop spring set-up looks better than leaf springs that
dont go down to the axle

[bhammer]

dieseldawg142,

So from what I gather it is okay to throw some blocks in the rear if they are steel, also putting 52 inch springs up front will be better for ride quality. I am not a big off road person, so I wouldn't have to worry about the bags. Where can I get a set of 52 inch leafs for the front? Anyone know which is the best to go with? I heard that the rear on my truck are 52 inch already. Not sure as I haven't measured them. I also plan on going with a crossover steering setup. Thanks for the help guys.

Brian

[Rubble]

Originally Posted by dbash

Great advice here, personally I don't like blocks in the rear either. If your going to lift it some you may as well try for a better ride all around.

I recommend that you ditch the factory steering arm and invest in crossover steering if its a daily driver. Its a huge improvement over the old "bump steering"

Deaver springs will make you a pack.

ORD (Off Road Design) has everything you need for the crossover steering.

My lift is a strong four inches with 33" tires.

My 86 has 4" suspension,3" body,is a daily driver without crossover steering & handles great.Same with my 82 on 6" suspension.No bump steer on either one & no crossover.Big thing is getting the whole front end in good shape,bad bushings,loose ball joints & tie rod ends make a huge difference.

[ryanroo]

I will toss in my $.02

i agree that blocks in the rear are ok, i like to keep them less than 3" personally. if you go this route, i like to keep my eye on the rear u-bolts for a while. its good to check all of them at 250, 500 and 1000 miles after the lift, but blocks put a little extra leverage on the bolts, and i am a bit neurotic about it.

i have heard, with no personal experience, that the 52s on the front are really squishy. so i would keep a sway bar in mind if you don't already have one. for my own preference, i would just go with stock springs. or if you were swapping, maybe go with 73+ Rancho springs. i have a 2.5" set of them on my FSJ and they ride wonderfully compared with other brands i have had.

now, on to steering. i will be the naysayer here. since you established that you aren't an off roader, i would keep the stock push pull steering. especially if you go to the long and soft springs, but do not plan on crazy off roading. the reason being is the motion of the leaf spring and the steering match(ish) in the stock format. the push and pull of the steering is easily counter acted by the spring. with cross over the steering will always try to push the springs side to side. this effect will be worse with more arch or softer springs. you can feel it in the cab. i have crossover on my jeep and i spent a great deal of time and effort in getting the geometry as good as possible. it still has bumpsteer. it has a hydraulic assist ram now, but before that i could feel it pushing the axle under the truck at slow speed or when trying to turn the tires while still. the only way to eliminate this and bump steer from a cross over set up is with a well designed panhard. i have been planning that for my jeep in hope of giving the steering a better feel.

[Rubble]

Diesel,I hear you about the blocks too,my 82 has blocks & it's way better suited for towing or hauling.My 86 has a suspension lift & its not as good for towing.Far as ride,pretty close one or the other...

[thiesnutz]

52" springs in the front are mainly for guys offloading. there real weird up front. you get more body roll type action. its been a few years since I've looked into but i believe with a 52" spring up front you have to run cross over steering. it can get real expensive trying to find a flattop knuckle for the passenger side and then getting it milled and tapped. don't quote me on that, like i said its been a few years since I've built a off road rig. if you still go that route, most 1/2 ton chevy rear springs are 52" and you can pick them up from a junkyard at a decent price, just check for cracked or broken leafs. in the rear you can get a shackle flip kit fro odd or diy4x. its a 4 inch lift that keeps your stock rear springs, and no blocks.

[dieseldawg142]

Originally Posted by thiesnutz

in the rear you can get a shackle flip kit fro odd or diy4x. its a 4 inch lift that keeps your stock rear springs, and no blocks.

or you could just use all of them

flips, blocks, stock leafs & bags!

[bhammer]

dieseldawg, I did some searching online and I like your setup on the back. I'm thinking of sticking with my stock springs and using a 4" shackle flip and throwing some firestone bags on it to keep it from sagging when towing/loaded. This will eliminate using blocks all together right? My concern is for the front set up. I want a more modern/safe/reliable set up on the front. So is installing a crossover steering a good idea? Is it more of personal opinion? How would I go about bringing the front up equal to the lift on the rear?

Thanks for the help guys, I'm learning a ton about this stuff from you guys. I think I got it dialed in, just need to figure out the best approach for the front lift, steering.

Brian

[dbash]

I already contributed my two cents on the crossover steering above. I suggest you consider beefing up your frame where the steering box is mounted. Your obviously going to be running larger tires/wheels and adding stress to this area. You can see an example of how I choose to do this at the beginning of my build thread. I have seen this part of the frame after it fails from stress and it's never a pretty sight. I don't want it happening to me.

Good luck.

[dieseldawg142]

bhammer, sounding like you want a smaller lift, & will be mostly on road, stick with something simple, some skyjacker or tuff country 2.5 springs up front, & blocks or 2" shackle flips out back, you might need a drop pittman. if your not going to seriously wheel it, i would just use lift springs instead of 52's.
more simple, the more reliable
i would do the front first, then bring the back up to match
cross-over steering, 2 trains of thought on this endless debate. ran it once on a 72 blaze with a 12" lift, was great off-road, not as great on the road, found it kicked the wheel more than the push-pull set up
my current crew has 8" lift & is mostly a camping & tow rig, stayed with a drop pittman, dropped drag link, & a steering block, been this way for yrs with tires ranging from 38" to 42", yeah, personal opinon & how deep your pockets are
and as mentioned, a steering box brace is always good too

[bhammer]

Allright thanks for the feedback guys, looks like I have a good place to start. I'll keep ya posted on what I wind up doing. All in all I've learned a thing or two about 4x4 suspensions. Thanks Dbash and Diesel... No 52s up front and sticking with stock. Going the simple route. Not looking for a crazy off road demon, just something that will handle some off road camping roads and still be great on the street. Thanks again....

[rogerapage]

I used the front leaf springs out of an 1979 ford F250. They have an off set center pin and all I had to do was to move the front spring hanger forward and the springs turned around backward. I removed the 2nd leaf and added two thinner helper springs. The Ford springs are wider so I widened the bracket. The rear shackle location seems to work fine. Tires are centered in the wheel well. I have over 125 hours on the hourmeter (speedo is off 5 mph, next on the list) I have had no problems at all driving. I plan on going with a 2-3 in lift as soon as the money tree blooms this spring. The truck is a high school class project so we tried different suspension mods just to see what works and what does not. One foot longer springs in rear with thinner helper springs. Longer springs in front. Ride on highway was improved. I have the factory steering linkage and have no bump stop or death wobble, up to 70 mph (GPS). Help this helps.
Roger Page

[rogerapage]

I used the front leaf springs out of an 1979 ford F250. They have an off set center pin and all I had to do was to move the front spring hanger forward and the springs turned around backward. I removed the 2nd leaf and added two thinner helper springs. The Ford springs are wider so I widened the bracket. The rear shackle location seems to work fine. Tires are centered in the wheel well. I have over 125 hours on the hourmeter (speedo is off 5 mph, next on the list) I have had no problems at all driving. I plan on going with a 2-3 in lift as soon as the money tree blooms this spring. The truck is a high school class project so we tried different suspension mods just to see what works and what does not. One foot longer springs in rear with thinner helper springs. Longer springs in front. Ride on highway was improved. I have the factory steering linkage and have no bump stop or death wobble, up to 70 mph (GPS). Rides great. Hope this helps.
Roger Page

[JimJones]

Couple of questions for you guys.
1. How do you measure what size leafs you have?
2. What is crossover steering and why do I want it?

[dbash]

JimJones

Regarding #2 Your going to get conflicting opinions on crossover steering. I have it on my truck because I was unhappy with the stock steering in my first lifted 69.

I copied this from Off Road Designs web site for you. They are selling the cross over parts so take it with a grain of salt and do your own research. There are plenty of illustrations of cross over steering if you google it.

"The straight axle GM trucks suffer from some serious steering problems, one of the biggest is due to poor geometry. The factory GM steering will fail to steer the truck when you're in twisted offroad situations. In fact, there are many times when the steering box is all the way to lock and the tires are pointed straight! Our solution to this is a "crossover steering" system where the draglink runs side to side instead of front to back. This dramatically improves the steering geometry and makes turning to the axle stops possible under all conditions."

[JimJones]

Originally Posted by dbash

JimJones

Regarding #2 Your going to get conflicting opinions on crossover steering. I have it on my truck because I was unhappy with the stock steering in my first lifted 69.

I copied this from Off Road Designs web site for you. They are selling the cross over parts so take it with a grain of salt and do your own research. There are plenty of illustrations of cross over steering if you google it.

"The straight axle GM trucks suffer from some serious steering problems, one of the biggest is due to poor geometry. The factory GM steering will fail to steer the truck when you're in twisted offroad situations. In fact, there are many times when the steering box is all the way to lock and the tires are pointed straight! Our solution to this is a "crossover steering" system where the draglink runs side to side instead of front to back. This dramatically improves the steering geometry and makes turning to the axle stops possible under all conditions."

What kind of "off road" situations is this applicable in? Does somebody like me who is planning on a mild lift if any at all tire size 33 - 35 max need to worry about?

[dbash]

Originally Posted by JimJones

What kind of "off road" situations is this applicable in? Does somebody like me who is planning on a mild lift if any at all tire size 33 - 35 max need to worry about?

There are plenty of these trucks on the road right now with stock steering and the mods your considering. Its a matter of personal preference and budget. Its not a major modification. you can add it later if you decide your uncomfortable with the stock set up.

[dieseldawg142]

Originally Posted by JimJones

What kind of "off road" situations is this applicable in? Does somebody like me who is planning on a mild lift if any at all tire size 33 - 35 max need to worry about?

would'nt even bother with it. unless you plan on stuffing your tires & getting COMPLETELY twisted up. i've skyed tires, dropped them a foot, buried them to the frame, & i have never experienced what ord says.
my blazer i ran cross over with 42's on a 12" lift-yes they are good off-road, but on-road you will feel it kicking your wheel more. for what you plan, a stock style set-up is cheaper, & has way better road manners. my crew is running 8" lift with steering block & dropped pittman & draglink (approx 10 yrs now) & i have never had steering issues with it, on the freeway at 55 or twisted up a 20 degree hill, it has always been 1 finger steering.
i have run both styles & unless it's a hardcore dedicated trail machine, i'll take the push-pull every time
JimJones, measure center to center the spring bushings. unless there custom or swapped out, they will be 2 1/2" wide