How to bag that truck of yours

[numatk_07]

I have an nbs but I thought this would be good info for an obs owner that wants to bag their truck. The info is genaric with some nbs specific stuff so do your best to weed out stuff you don't need.

copied from other site:
I know there has been multiple threads on this but I want to show how I bagged my nbs. I tried to keep most of the info generic but I also threw in some nbs specific information. I have recieved multiple private messages asking for my build thread or general air bag questions. So here is my explination, opinions and how I did it. If you have any general air bag questions or nbs air bag questions feel free to ask me and I will update this thread to answer the question.

To start off I want to explain how an air bag system works. The heart of an air bag system is the air management. You have to have a way to compress the air and then store enough of it to fill the 4 seperate air bags that will support the truck. I use an engine driven compressor but some other people use 1 or more electric compressors. The compressors are turned on using a pressure switch. When the pressure drops in the air tanks to a certain level the pressure switch shorts and completes the electric circuit to turn the compressor on. I use 2-5 gallon tanks to store air which is plenty to lift the truck to ride height from the ground. The minimum pressure switch I would recomend would be a 150psi, and the maximum I would recomend is 200psi.

With the air stored in the tanks there has to be a way to transfer the air to the bags. Some people choose to control the front air bags together and back air bags together but I prefer to contol each bag separately. To control each bag separately you will need 8 valves. 4 of them will fill each bag and 4 will dump the air out of each bag. When I first bagged my truck I used an avs-9 switch box to control my 8 valves. It has 9 switches that can control each bag individually, the front, back, left, right, or all bags at once. Asside from 8 individual valves there are valve manifolds availible also. I have upgraded from 8-3/8" valves to 1 Accuair VU4 manifold. And instead of the avs-9 switchbox I upgraded to the Accuair E-level. For more info on Accuair go to gmfullsize.com and search accuair or go to accuaircs.com.

Installing the front air bags is simple. All you need is the air bags and some cups to make the desired length between the lower control arm and the spring pirch. I also used a 2" drop spindle. But, on an obs, to lay out, you will need to do some trimming to the spring pirch and make room for the tie rod. When you get to that stage you will have to figure out what to cut.

The back is way more complicated. There is an infinate number of ways to do the back so I will just explain the basics and go more into depth with what I have. No matter what you choose to to do you have to get rid of the leaf springs and the hangers that hold them to the frame. To control the axle you can use a 2, 3, or 4 link. I have what is considered a 6 link but it is basicaly a 4 link with extra attachments to attach the bags to the axle. You will also need a way to keep the axle from moving side to side (unless you use a tri-4 link or wishbone). I used a watts link but a panhard bar works also.

I will continue to add info to this but this is atleast a start for now. If I left something out or you have questions please feel free to let me know.

 

[C. Hoag]

good write up man, did you have to change anything on the steering tie rod end joints or anything on the front? Other than the spindles you did nothing else but put bag cups in? Did the cups bolt in or weld in?

 

[numatk_07]

I replaced the inner and outer tie rods with moog. Only the outers got more articulation than stock ones. The cups are bolted in on top and floating on the bottom. I have done a lot to the front but all that was needed was bags cups and spindles. The tire hit hard on the brake booster so hydroboost was needed also. Keep in mind none of this info is relivant to 88-98 trucks.

 

[Ginger]

lol, i need to get my details on how to do the front of mine, ill prolly talk to dava flava cuz he had one

 

[Marcos]

I just figured i would throw a thread up because this questions gets brought up directly and indirectly every week. I know something like this would have helped me immensly when I was starting my bagging. Here is what you have to do to lay full frame on 22's with a 265/35/22" tire on an OBS. I will add pictures with each step if I have them. The pictures I have are not the cleaned up and finished, but enough to give you the mental picture. Dont rag on the pictures because some look like crap

Front- In some kind of order- Not using aftermarket control arms. Modifying your stock ones work fine and will save you some serious scrilla

Remove stock inner fenders as well as the entire front clip (fenders, grille, bumper etc. Core support can stay. This makes it a hell of a lot easier to move around)

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Rolled fender lips

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Everything that is mounted on the drivers fender should be unbolted. I know it looks like a pain, but onces the brackets are unbolted everything moves freely. The fuse box can be mounted by the brake booster and the ABS controlled can be mounted near the same area. You can decide when the time comes how you want to mount this stuff. Some put a bar from the brake booster to the core support and mount items on this.

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If using SD.com cups, cut the top cup to 2.5", leave bottom cup how it is. This will ensure as much lift as possible while still laying out.

Notch the frame for the tie rods, cutting only a little at a time until it lays out.Once you cut it out, you should weld a half piece of pipe inside the notch you just cut. This will strengthen the frame where you just cut. Now to note I have not done this yet. I have over 10k miles on it and no signs of any extra stress/flex/anything. Not recommending it, but just saying

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Cut outer side of the spring pocket enough so the bag will not hit anywhere. Also cut around the inside of the spring pocket to ensure clearance.

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"De-hump" the lower control arms..this is cutting the front,top part up the arm on the so it doesnt hit the frame. re-weld a plate on the top to give them their strength. Also at this time remove the bump stops from the control arms.

Notch the frame above the control arm. this is so when the arms move up, they will not hit the frame. notch accordinly to not take to much out. Not very much is needed. Maybe an inch.

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Install 2" drop spindles. If running the 15" stock wheels, you will have to trim the "rain gutters" on the sides of the control arms. If you dont, the wheel will hit these and you wont be able to use the wheels.

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Reinstall everything and test it out..you can cut more on the tie rods, and above the control arms if its still hitting..remember you want a little extra room incase you hit a dip while riding real low..even though the frame may be on the ground, the front end can still travel up higher, bending tie rods(found this out the hardway)

"Massage" firewall or cut it and weld in tubs. There is not very much that hits..You can take a mallet and pound it back and you will never tell the difference. IMO it wasnt worth it to weld in tubs for 22's.

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The wheel will hit right above/behind the wheel where the curve ends..right by that black box. you will have to cuz that black box in half..its just a drain for the wiper cowl..pound it in where it comes to a point at the top of the curve and you will be good

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You will have to move the wiring harness in the firewall on the drivers side. What i did was cut a relief to the left of it and slid it up and over about 3-4 inches. You can cut a hole the same size as the stock hole and it will mount right in there. Make sure the stock hole is sealed up good to keep water out of the cab.
Not finished pic, but you get the idea how far to move it

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Set outer fenders back in..you wil have to notch out the inner part of these fenders where the "bracing" is. Once again only notch it enough to clear the wheel. This will ensure you have the smallest tralier fenders and can still keep the battery in the stock location.

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Weld in traler fenders and ensure they are braced properly.

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There are some little things here and there that you will run into. It is different on every truck so tackle those as they come. This is the general way to do it.
Bam

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Middle
Remove tranny crossmember. Weld tabs on the side so it can bolt in through the side of the frame rather then on the bottom


Rear-
The kit you choose is your choice. there are 2 links, 3 links, 4 links and 6 links..all depends on preference and is covered in "Advice on bagging a truck"

Raise stock gas tank. notch the stock crossmember abouve the gas tank so the tank will sit higher. Dont need to do anything with the front mount,

Notch gas tank crossmember for drive shaft(also may have to notch the back of the cab on a regular cab truck)

Must do a weld in notch. An under the bed notch will not cut it. an 8" notch should be enough. I went with a 10" and im way over notched. You want it properly notched and with bumpstops so when riding cali your ass end wont drag and your gas tank will be safe..
Can you say enough to lay on 26's? whoops

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Ensure your pinion angle is good at ride height and when riding lower to avoid vibrations and accelerated wear on parts.

Cut out bed above the notch and around the wheels. be sure to cut accordinly, I cut to far out and now im limited to square tubs in the rear unless i do a bunch of sheet metal work.

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How my tanks are mounted. Take note I have a hidden hitch as well. You have to offset the tanks like I did to get 15 gallons to fit under the bed with a watts and hitch..I was proud of it lol..Marcos you need to get it done

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This is all I can think of right now..feel free to add any information that I may have missed. This may have been done already, but i didnt see any quite as detailed..let me know if im an idiot..
What you have to look foward to..layin frame on 22's

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From FSC by Nickleahy23

 

[Ginger]

perfect thanks man

 

[C. Hoag]

what set up did nick have? 2 link or 4 link?

 

[Ginger]

he had a 6 link

 

[numatk_07]

Thanks marcos. I was hoping someone would jump in with obs specifics.

 

[Marcos]

Cool, just trying to remember all the great threads we had on other forums that were never made stickies