Triangulated 4-Link on Air Bags

[FromTheDust]

View attachment trim.upvtSi.MOV
Hopefully that worked, [it worked! click the link above to see the video of the rear end suspension] I tried to post a video from my iPhone. This is the first post on my build, it's still a work in progress. It should be done sometime this May. The limit straps and shocks still need to be added along with all the controls for the airbags. I got the glad hands powder coated and reinstalled earlier this week.

 

[Kohburn]

looks clean. how much travel will that setup allow?

 

[FromTheDust]

With the bags being the limiting factor, 10 inches. Neutral set at a 6 inch lift from stock height for the 16R20XZLs and +or- 5 inches of travel. But before that got installed we set the frame on the axel and took it to 30 inches before the jack ran out of travel. Some pictures of the flex at the level frame ride height before the airbags.

 

[welldigger]

I dig the 4 link set up. If your going to fun 53's how do you plan on lifting the front?

 

[FromTheDust]

I still have to fabricate the cross tubes I'm gonna use 2" .250 wall DOM left over from the links. And a picture sitting level with the 4-link in sitting on rounds of wood and front lift installed. . . . These pictures are coming out of my iPhone all sorts of directions.

 

[welldigger]

That's gonna be one awesome truck.

 

[FatBuddhaBoo]

And I thought my S10 on airbags was sweet...very nice! Looking forward to seeing the completed project now.

 

[Birdman]

I know ths is an old thread. Is this suspension road legal or a trailer queen?
Would it pass a DOT inspection?
How do you keep dirt from wearing out the unsealed heim ends?
TMR Customs sells this as off road only. A truck like this is for sale and I am wondering if I would not be able to drive it on the road.

 

[M-1028]

I know ths is an old thread. Is this suspension road legal or a trailer queen?
Would it pass a DOT inspection?
How do you keep dirt from wearing out the unsealed heim ends?
TMR Customs sells this as off road only. A truck like this is for sale and I am wondering if I would not be able to drive it on the road.

I don't see why not, it's no different than installing air bags on a lowered truck. They have no problems with dot around here. All hiems should have a seal, they are usually injected with Teflon. They hold up to off road use very well.

 

[FASTNOVA]

That is sweet! Now if someone would just do that with a M939 all around.

 

[jesusgatos]

How do you keep dirt from wearing out the unsealed heim ends?

Rubber boots like these are a great investment if you're running heim-joints on anything.

 

[Birdman]

Thanks;

That looks like the ticket.
None of the ends I have seen have scraper seals. Dirt would wear out the teflon in no time.
Also most have unplated or cad plated balls which would rust in road use and wipe out the bearing.
We have roadside dot inspectors who are just brutal nit pickers on heavy trucks.

 

[jesusgatos]

Dunno what those DOT inspectors are looking for, but you might want to give my friend Mark at Lite Industries a call. He's up your way and can probably tell you what you need to know.

 

[Birdman]

Thanks for the link gatos.

Here, if the tare weight is over 12,000# the truck is commercial and subject to annual CVI including pulling all wheels and measuring the drums.
Bobbing would get around that but you know the inspectors will be staring at you.
I have seen truckers fined for having a bolt in a clevis instead of a pin. INFERIOR SUBSTITUTE! RBC Bearings calls their heim ends industrial or aircraft, not automotive. Backyard engineering would be just what these guys are looking for.

 

[jesusgatos]

Sure thing. Lite Industries does a lot of custom work on bigger trucks, outfitting and upfitting rigs for all kinds of companies up there. Mark is also an off-road guy and a top-notch fabricator.

 

[rustystud]

Great Build !!! There are some talented folks on this site ! I especially want to see how you will mount the air bags.

 

[FromTheDust]

In the first post there is a link to a video of these bags installed! This was how we fabricated up the mounts. That were welded to the axel and reinforced the fame where the bags bolted on.

 

[FromTheDust]

We relocated the air tanks to make room for the links

 

[Birdman]

I see that the axle and pinion shaft changes pitch when the suspension moves up and down.
This is caused by the upper links being shorter than the lowers.
For a cardan joint shaft to deliver constant rotational velocity the shaft angles have to be equal at both ends and the joints yokes synchronized. i.e. pinion parallel to transfer case, yokes aligned. I have made this mistake myself.
Torsional vibration is not friendly to ujoints and gear teeth. If you can maintain constant ride height it might not be too bad.

You have achieved a high degree of articulation but your suspension has no inherent roll stiffness.
An anti-roll bar would be a good idea since the centre of gravity is far above the roll centre on a loaded truck.

 

[FromTheDust]

I'm not too concerned and let me explain why. The truck is essentially a 6" lifted bobbed deuce to accommodate running on 53 inch tires. The front end was lifted with blocks and an extended pitman arm was created. We keep pondering power steering but that's another thread. Now for the rear end we wanted to build something cool that fits the truck. Adding blocks and front end springs just didn't seem fitting. We wanted a truck that is built as strong underneath as the body looks. So with the 4 link installed and 53 inch tires and the bed it has only a limited 10 inch travel. When the 4 link was designed it was built specifically for the 53s. The axle was setup to be level while the truck is lifted and level in the normal ride location. From that point the rear axel only has -3 +7 inches of travel, not the 30 inches the links are capable of. The distance from the transmission to the rear axel was lengthened by about 4.5 inches with the change from two axels to one axel. So with the increased length of the driveshaft, a limited travel in normal operations, proper setup when the truck is level on 53s I do not foresee any catastrophic problems. The angles are pretty close the original design. This truck is designed to be a road truck that can go in the dirt just like any other good truck. I've got CA plates for the truck and matching trailer when it gets all finished up. Just got caught in life, well see when this truck hits the road.