front suspension mods AKA - ride improvement mods AKA - butt happiness mods

[Buffalobwana]

I would massively over-engineer anything I did to it.

Yep, me too. It should almost go without saying that this is a given. It's a big truck, you gotta think big.

It is against the law in a lot of states and very unsafe to use ANY lift blocks on the front axle. Unless you just want it to snap off and the whole front of the truck laying all over the highway. But some folks are adventurous.

In my first post, I floated an idea, that I still believe is viable. I would remove a couple springs and render them useless by making cuts in them, X's or cut out small circles, then reinstalling them. No change in height, no blocks, no snapping and exploding trucks. Add adjustable air bags to compensate for the rendered useless springs.

It's a dead end road though. It either works and I'm a hero, or I am shopping for new springs. Personally, I don't see how it couldn't work. It is softening the ride, but you have air bags as a backup. It's adjustable, so it can be fine tuned.

Thanks to everyone who contributed ideas.

 

[Floridianson]

Would have to agree with above, seat and if so cab air ride. Lower tire pressure if not hauling and see if that helps. I have done a few trucks with up grade air ride seats and it was a huge difference.

 

[Rmtaunton]

Not a fan of lower air pressure heats tires and they blow quickly ask coffee


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[Buffalobwana]

Something I noticed while driving yesterday, and trying to pay attention to the movements that I want to dampen, is that it's not necessarily the up and down motion that beats you up, there is a forward and backward "bucking" that you don't really notice unless you are paying attention, that beats you up pretty badly.

Dampening the suspension would have an effect on that as well. Just curious how much.

Floridianson, you brought up something I wondered about and that is air ride cab. While a full commercial style air ride cab wouldn't work, it's not designed to, there does have to be some tweaks that can be done to the cab mounts to soften it a bit.

I believe comfort is gained incrimentally. Air ride seat is probably the biggest jump, but, spring mods, air bags to take some of the weight off the springs, and cab mount mods all together might just make a bigger difference than we know.

Im sure the design of the back axles, while great for off-roading, contributes a lot to the bucking sensation. Just a thought.

 

[someoldmoose]

Lowering tire pressure, AND RAISING, to match the load is absolutely the best, fastest, and easiest way to make your truck ride and handle at it's ultimate potential. The KEYWORD is L O A D. Increased pressure with no load will wear out the center of the trad more rapidly, ride more harshly, and put more of the road impacts into the suspension when it could have been dissipated in the tires. The ONLY upside to slight over inflation if reduced rolling resistance, ergo, slightly more m.p.g. HOWEVER, it also means reduced BRAKING traction. Anybody ever been sideways on an Interstate in rain / snow at 35 m.p.h. after Freddie or Fannie Fourwheeler did something stupid in their SUV (JUST HAD TO PASS ME IN THE SLUSH FILLED PASSING LANE DIDN'T YA DUMBASS) ? NOT A FUN RIDE

OBVIOUSLY, UNDERINFLATION IS DANGEROUS. Overloading even more so. That is why almost every MV has tire pressures for Highway, Cross Country, and (on some) Emergency on the data plate. THAT being said, a 5 ton running empty and a 5 ton running at max. payload SHOULD have completely different pressures. USE THE CRAYON / CHALK CHECK during pre-trip and after any change in loading or GROSS change in atmospheric temp. (gets a lot colder up in them thar hills as ya climb)

 

[jbayer]

In my first post, I floated an idea, that I still believe is viable. I would remove a couple springs and render them useless by making cuts in them, X's or cut out small circles, then reinstalling them. No change in height, no blocks, no snapping and exploding trucks. Add adjustable air bags to compensate for the rendered useless springs.

It's a dead end road though. It either works and I'm a hero, or I am shopping for new springs. Personally, I don't see how it couldn't work. It is softening the ride, but you have air bags as a backup. It's adjustable, so it can be fine tuned.

Thanks to everyone who contributed ideas.

I don't think that would work. Leaf springs are tempered. You'd have a tough time drilling holes, a torch would take out the temper. Even if you used a waterjet, they'd be so weak at the cut-outs, they would snap at some point.
Maybe shorten them some, but no cut-outs.

 

[simp5782]

You can debate that with the millions of 4x4's that use them legally. If I were to do as the OP asked and for some reason it HAD to be the suspension to change then I would massively over-engineer anything I did to it. But if it were me, I would change the seat and the cab to air-ride instead.

No they don't. None of them run a lift block on the front with a leaf spring. Maybe a spacer with a coil spring but not a lift block on any type of leaf. A lift block is solid and your spring flexes. Your block then becomes a leaning house of cards on a turn and the block will flex right out and snap the U bolt or the block will pop right out. On the rear it does not have near the forces going against it as the front does when it comes to turning. Even with an alignment pin on the springs lined up with a block the block will pop right out from under it or snap it off. They have a spring lift piece that goes in the front of F250s and 1 tons that has some flex to it and is essentially just springs on top of each other and then U bolted in. Plus I do not know a piece of material in this world I would trust to be in a block form that I would bolt under the front of a 5 ton to even consider it to be safe to drive on. The forces these trucks make especially when hitting some of the craters on the road is tremendous. And we haven't even considered the braking force the front axle takes when you slow that 22,000lb truck down. Snap, crackle, Split it.

I have never even see a lift kit for any truck that offers a front block.

 

[Mos68x]

I have to agree with you Moose, LEOs can be downright vindictive if they think you are challenging them. Now I'm not saying to take it lying down, but it's better for us to just say 'yessir' and move on until the court date, then you can take in copies of the legislation in your defense and they will most likely drop all charges/violations as long as you haven't done anything stupid. Make no mistake, in general I hate LEOs because they most often abuse their positions, but I also dislike being in jail just because of a disagreement with them as well. Besides that, if you get pulled over by the same officer or Dept you can then file for harassment as well. Just make sure that you have all your ducks in a row first. You could carry those same copies with you beforehand if you feel as though it may be challenged by an LEO, but I would play it by ear with the officer but always be respectful and disciplined.

 

[Mos68x]

Since I mentioned the air ride cab, I've really been thinking about its feasibility. I just took pictures of my truck and I think it could easily be done.

The mount for the front of the cab (cab side) has convienient round holes above the body pucks that could be modified to hold a pivot point.


I would've been concerned about the steering and High-Low shifter for the transfer case, but they are either remotely mounted or have a u-joint to allow for movement, in this case forward rotation.


Thereis plenty of room between the chassis and cab to allow for an air-bag, I would just use some Helwig's that are meant for a pickup like the ones I installed on my Chevy Silverado 1500.


I would try try to keep some rubber at the rear mount location so that you have some sort of bump-stop. It would be better if one could lower the rear mount so that you have some travel, but without changing the transmission mount since it also located on the same chassis cross-member.


The other things you would have to modify would be the mounting locations for the intake and exhaust since they are mounted to the cab and not to the chassis. The biggest problem of those being where the intake passes through the mudflap, you'd have to make sure you had enough clearance to allow for 'suspension travel'.


Another consideration ion would be where the hood meets the cab since that will now be a moving point because of the air-ride setup. I think it's possible, at least with the A2's since I don't know how much room is between the cab and engine on the NHCs, but it would require some careful thought and planning to make it work nicely. I will say though at first glance it's almost as if the original engineers had it in mind as a future possibility, because it looks like it could be an easy build once you got past the engineering and planning.

 

[Floridianson]

Yea agree way under inflated is bad but believe he is running a 923. The rear suspension of that truck is stiff. Running unloaded 5 to 6 pounds lighter hot might let the sidewalls take up just a bit of shock. As many said if you were looking for a soft ride it won't happen with that stock set up. I would carry the front at or close to specs.
Don't know what happened to Coffee but if it was the Hemtt then with the tare weight of that truck on singles and the age if any then yes to low tire pressure will catch up and more so if higher speeds are there.

 

[someoldmoose]

Since I mentioned the air ride cab, I've really been thinking about its feasibility. I just took pictures of my truck and I think it could easily be done..

You sir, may join my engineering battalion any time. Easy though, I do not believe it would be. Worthwhile if one drives the vehicle a bunch ? ( I know many on here actually USE their rigs commercially, Kudos to them ) ABSOLUTELY. It would take a whole lot of trial and error, design and redesign, but once complete it would be AWESOOOOOOOME. I personally would bag the front clip as well so that it moves with the crew area. It might require some sort of sub-frame to tie the firewall and radiator support together but that's easy.

Not a project I would undertake but I can definitely see it being worthwhile to those that spend lotsa seat time. ​

 

[lindsey97]

No they don't. None of them run a lift block on the front with a leaf spring. Maybe a spacer with a coil spring but not a lift block on any type of leaf. A lift block is solid and your spring flexes. Your block then becomes a leaning house of cards on a turn and the block will flex right out and snap the U bolt or the block will pop right out. On the rear it does not have near the forces going against it as the front does when it comes to turning. Even with an alignment pin on the springs lined up with a block the block will pop right out from under it or snap it off. They have a spring lift piece that goes in the front of F250s and 1 tons that has some flex to it and is essentially just springs on top of each other and then U bolted in. Plus I do not know a piece of material in this world I would trust to be in a block form that I would bolt under the front of a 5 ton to even consider it to be safe to drive on. The forces these trucks make especially when hitting some of the craters on the road is tremendous. And we haven't even considered the braking force the front axle takes when you slow that 22,000lb truck down. Snap, crackle, Split it.

I have never even see a lift kit for any truck that offers a front block.

What simp said.

DO NOT cut on the springs, they are heat tempered, and also have retaining pin bolt thru the center of the pack, and there is a lot of energy stored up in a leaf spring assembly. Be very careful when disassembling a spring pack. DO NOT add a lift block on the front axle to ANY vehicle. Braking forces will snap the u bolts, or allow the block to create leverage on the spring pack and ultimately fail when you least expect it. Most lift blocks are cast, and aren't very strong anyways. I cannot imagine where someone would find a lift block to fit a M939 truck.

DO NOT reuse u-bolts, they stretch and are supposed to be replaced. Also be sure to torque them in an X pattern and be sure to know your correct torque amount. Check them for correct torque after driving the vehicle for 100 miles.

I think you are confused as to the type of hydraulic suspension I was referring to. Think monster truck suspension, like Bigfoot. Hydraulic suspension is infinitely adjustable, has very little stiction, which will help with travel and response time to bumps or variance in the road surface.

Have you given thought to purchasing brand new steer tires, having your current ones balanced, or shaved to make them perfectly round again?

 

[someoldmoose]

I second,or third, what was said above. NO LIFT BLOCKS on front solid axles, E V E R ! I think I saw the O P say lift blocks were NOT part of his equation but for the masses.


I would accept the plan if the main leaf and perhaps the next one or two were left in place, and the Commercial truck air bag of a proper rating was used on top of the u-bolt to provide the vertical springing, leaving the leaves to do the locating of the axle. A full - up hydraulic job is awesome but very expensive. For what that would cost you could buy an air ride for your air ride seat and float along on a cloud.

Pffeeeeew ! (wipes sweat from brow)

 

[quickfarms]

Funny thing about this thread being here now.

I weighted my truck by the axle on the way to the spring shop this morning.

They are going to remove the rear springs and reduce the capacity so it is more in line with the camper that i carry.

So my advice is to have a reputable spring shop do the work so it is correct and will pass dot if needed.

They are also going to add shocks to the rear

On the subject of lift blocks on big trucks. They are very common but are only used to level the truck and are available in 1" and 1.5". Also .5" is just a short leaf. Both of my class 8 trucks have them on the front axle.


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[Csm Davis]

I second,or third, what was said above. NO LIFT BLOCKS on front solid axles, E V E R ! I think I saw the O P say lift blocks were NOT part of his equation but for the masses.


I would accept the plan if the main leaf and perhaps the next one or two were left in place, and the Commercial truck air bag of a proper rating was used on top of the u-bolt to provide the vertical springing, leaving the leaves to do the locating of the axle. A full - up hydraulic job is awesome but very expensive. For what that would cost you could buy an air ride for your air ride seat and float along on a cloud.

Pffeeeeew ! (wipes sweat from brow)

What simp said.

DO NOT cut on the springs, they are heat tempered, and also have retaining pin bolt thru the center of the pack, and there is a lot of energy stored up in a leaf spring assembly. Be very careful when disassembling a spring pack. DO NOT add a lift block on the front axle to ANY vehicle. Braking forces will snap the u bolts, or allow the block to create leverage on the spring pack and ultimately fail when you least expect it. Most lift blocks are cast, and aren't very strong anyways. I cannot imagine where someone would find a lift block to fit a M939 truck.

DO NOT reuse u-bolts, they stretch and are supposed to be replaced. Also be sure to torque them in an X pattern and be sure to know your correct torque amount. Check them for correct torque after driving the vehicle for 100 miles.

I think you are confused as to the type of hydraulic suspension I was referring to. Think monster truck suspension, like Bigfoot. Hydraulic suspension is infinitely adjustable, has very little stiction, which will help with travel and response time to bumps or variance in the road surface.

Have you given thought to purchasing brand new steer tires, having your current ones balanced, or shaved to make them perfectly round again?

No they don't. None of them run a lift block on the front with a leaf spring. Maybe a spacer with a coil spring but not a lift block on any type of leaf. A lift block is solid and your spring flexes. Your block then becomes a leaning house of cards on a turn and the block will flex right out and snap the U bolt or the block will pop right out. On the rear it does not have near the forces going against it as the front does when it comes to turning. Even with an alignment pin on the springs lined up with a block the block will pop right out from under it or snap it off. They have a spring lift piece that goes in the front of F250s and 1 tons that has some flex to it and is essentially just springs on top of each other and then U bolted in. Plus I do not know a piece of material in this world I would trust to be in a block form that I would bolt under the front of a 5 ton to even consider it to be safe to drive on. The forces these trucks make especially when hitting some of the craters on the road is tremendous. And we haven't even considered the braking force the front axle takes when you slow that 22,000lb truck down. Snap, crackle, Split it.

I have never even see a lift kit for any truck that offers a front block.

It is against the law in a lot of states and very unsafe to use ANY lift blocks on the front axle. Unless you just want it to snap off and the whole front of the truck laying all over the highway. But some folks are adventurous.

Okay cool your heels guys, we are not talking about a 4" block made for a Chevrolet pickup. More like a 1" solid steel block made to be part of the spring pack like a "easy-inch", look them up. They can't just slip out and cause a wreck. Or just cut off all but an inch or two outside of the u-bolts of the springs you want to remove, this will keep the axle where it is supposed to be and the air bag will hold up the weight. You could also just weld a solid piece of steel to the axle mounting pad it will not pop out. There are several ways to get the axle to be where it is supposed to be and the air bag in place.

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[Csm Davis]

As to the air bag cab it can be done but you should bag the rear axles first if you are wanting softer ride.

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[someoldmoose]

Csm Davis, you are correct but nobody mentioned a Class 8 compatible "easy inch". Used them regularly over the years when the springs sagged on fire trucks. As I said, I don't even think the OP was planning anything like a "block" of any kind. I also agree that bagging the rear would DRAMATICALLY improve ride comfort. Personally, I would not go that route because I have never seen an air-ride with anywhere near the articulation of the spring bogies. Might exist, just I've never seen one. I'll trade capability for comfort any day and twice on Sunday, but then I won't be driving 600 miles a day in "Exit Strategy" either.

 

[doghead]

The suspension needs a computer...

Just put it "limp mode"!

Computers are good.

 

[Buffalobwana]

I don't think that would work. Leaf springs are tempered. You'd have a tough time drilling holes, a torch would take out the temper. Even if you used a waterjet, they'd be so weak at the cut-outs, they would snap at some point.
Maybe shorten them some, but no cut-outs.

i was planning on a plasma cutter. But, didn't think they would break. I did think it would effect the temper of them, but not that severely. Good to know. I think you are right, say, cutting the last three short, like the last and smallest one, would in effect, be a giant "block" allowing the springs above it to take the weight of the shortened spring. It would also effect the temper, just by cutting the ends. But, since there would be little movement, I doubt it would make a difference.

Then, find the appropriate big truck air bag to compensate for removed suspension. Adjustable, so you can take it all the way back up to factory specs if you wanted to, but also, dial it down for empty driving around town.

Lets face it. Suspension is supposed to do a few things.
Support the truck, and its weight under uneven road conditions
GIVE when the tires hit bumps, potholes, rolling parts of the road etc.
Level out the ride as much as is practical.

The springs on the truck are overbuilt. They are meant to carry 5 tons off-road and survive the most unforeseen bumps. They are too **** heavy for what we do with them.

Thatis is the key phrase here "What we do with them". I drive mine to the G store, Dr appointment, Cabelas, wherever I want. When I need to haul a load, I can with a trailer, or in the bed. Neither of which effect the load on the front to any significant degree.

 

[Buffalobwana]

Okay cool your heels guys, we are not talking about a 4" block made for a Chevrolet pickup. More like a 1" solid steel block made to be part of the spring pack like a "easy-inch", look them up. They can't just slip out and cause a wreck. Sent from my SM-G930V using Tapatalk

Right! I think there were some misunderstandings in reference to blocks. Everyone had valid points, but, nobody was on the same page.

No, I never considered blocks for all the reasons stated. Other than the springs themselves as a really long block.