Front air bags. What did I do wrong?

[stomper]

It takes over 100 psi to get the inner fenders off the tires. And then I barely have clearance to roll. I have 2" cupped LCA, 3" drop spindles, and 2600lb Airmaxxx bags. Suspension is all lubed and moves freely. Specs say max bag height is 9". I read an Air-Lift Dominator is 12.5". Maybe different bags is what I need? Too much spindle drop? Did I just mess up on this combo? Gonna get under there and start measuring bag heights today. Truck pic top is aired up and bottom aired out.

[HO455]

Measurements will help. In the meantime have a couple of questions.
Other than wheels and spindles your set up is similar to mine.
Will bags move the truck higher with more air pressure?
Do you have a second guage to test the accuracy of the one you are using?
Can you share more information on the air side of your installation?
And last but not least can you post some photos of the bags aired up and out?

[lolife99]

I would try a different air bag.

[stomper]

Originally Posted by HO455

Measurements will help. In the meantime have a couple of questions.
Other than wheels and spindles your set up is similar to mine.
Will bags move the truck higher with more air pressure?
Do you have a second guage to test the accuracy of the one you are using?
Can you share more information on the air side of your installation?
And last but not least can you post some photos of the bags aired up and out?

I don't have a convenient way to get more air pressure in the bags or attach another gauge. I trust the gauge though within 10 psi and my air system is maxed out at a hundred. Viair 480 pump and 3 gal tank with manual valves and 1/4" line. Sorry about the upside down pix. They are correct in my phone.

Update: Bag height is 6" at 100 psi

[HO455]

I can't tell from the photos. Do you have cups on the bottoms of the bags? The photo is of one of my bags. The cup is bolted to the bottom of the bag. And if you look very closely to the left in the background are the old bags I replaced with the cups on them.

Here is a link to my Burban repair thread. There is information on what I did to my front suspension scattered over several pages for the most part starting on page 9. You may find something useful.

https://67-72chevytrucks.com/vboard/...=698377&page=9

[lolife99]

That bag looks like it’s just ballooning and not raising.
Try a AirLift Dominator bag or a Slam Specialties bag.

[jayoldschool]

Cups I think are needed. I'd also suggest a Slam Specialty bag. And maybe bigger lines?

[stomper]

lolife I think you're right on. I ordered some AirLift Dominator D2600's. I read they are a little bigger around which would help with the pressure and have a longer stroke which would help with the height.

[Willie Makeit]

you got 5" of static drop to compensate for (3" spindles / 2" cup) and that is a LOT of travel to overcome before ever lifting the truck. I've ran 2.5" spindles and stock lower arms with flat plates in the past and the truck rode at ride height with less than 50 lbs of pressure.

[MattyBs71]

Jared the Dominators are great bags I had them on the 68 GMC with cupped lower arms like you. The only problem is my cups were not big enough and would rub at some point during travel on side of cup. Which blew bag. I suspect your cups are the same diameter as mine or smaller looking at your pics. I got Slam Specialties that aren't as fat as Dominators. They don't lift quite as high as the Dominators but don't rub in the cups.

[stomper]

Originally Posted by MattyBs71

Jared the Dominators are great bags I had them on the 68 GMC with cupped lower arms like you. The only problem is my cups were not big enough and would rub at some point during travel on side of cup. Which blew bag. I suspect your cups are the same diameter as mine or smaller looking at your pics. I got Slam Specialties that aren't as fat as Dominators. They don't lift quite as high as the Dominators but don't rub in the cups.

Matty, I am surprised to learn there is so much difference dimensionally (and thus performance) between bags that are labeled as '2600'. This is exactly the response I was looking for but not what I want to hear as I already ordered the Doms. My cups are 8-1/4" ID. I guess I'll bolt 'em in and see how they do. You must know my truck from NWC10's or something!?

[MattyBs71]

Originally Posted by stomper

Matty, I am surprised to learn there is so much difference dimensionally (and thus performance) between bags that are labeled as '2600'. This is exactly the response I was looking for but not what I want to hear as I already ordered the Doms. My cups are 8-1/4" ID. I guess I'll bolt 'em in and see how they do. You must know my truck from NWC10's or something!?

Sorry to be the bearer of that news. Yes I know you from NW C10's I have "Willy" the 68 baby blue LWB GMC with the Topper and "Betty" the 71 Aqua SWB.

[stomper]

Airlift dominators is what I needed. Ride height at 80 psi. I think they do touch the edge of the cup but wouldn't if my top plate were better centered. Pic of Airmaxxx vs Dominator.

[MattyBs71]

Yeah. See they are YUUUUGE. LOL They will last about a year give or take rubbing before they blow. Don't ask me how I know.

[HO455]

I went with the Slam Sevens and built my arms to accommodate them without rubbing.

[jarrodblake]

It sounds like something is binding. I'm running 3800 5k bags in the front of my C30 with a cummins, and it only takes 40 psi to get to stock height/ ride height, and 60 psi at max lift. Maybe try and disconnect your sway bar? That or you control arm bushing are to tight causing them to bind, were you able to freely move them up and down when you installed them?

[Richard]

Originally Posted by Willie Makeit

you got 5" of static drop to compensate for (3" spindles / 2" cup) and that is a LOT of travel to overcome before ever lifting the truck. I've ran 2.5" spindles and stock lower arms with flat plates in the past and the truck rode at ride height with less than 50 lbs of pressure.

The way you are looking at it would the mounting plate on the upper spring cup kind of zero out the arm cup.

[Willie Makeit]

Originally Posted by Richard

The way you are looking at it would the mounting plate on the upper spring cup kind of zero out the arm cup.

no sir, i ran upper plates as well.

[stomper]

Originally Posted by jarrodblake

It sounds like something is binding. I'm running 3800 5k bags in the front of my C30 with a cummins, and it only takes 40 psi to get to stock height/ ride height, and 60 psi at max lift. Maybe try and disconnect your sway bar? That or you control arm bushing are to tight causing them to bind, were you able to freely move them up and down when you installed them?

Good suggestion jarrod. The sway bar is really tight with fresh poly bushings and the appropriate grease but, no different with the sway bar disconnected. Although stiff, the control arms were able to be moved by hand before I put it all back together.

[SCOTI]

Just for comparison, my 89 CC Squarebody w/a BBC/TH400/PB lower arms/Firestone F7325's (8" dbl convoluted bags) takes ~100psi to achieve ride height.

[HO455]

I went and looked back at photos and posts from when I first got my Burban to see if I could find anything more to help you. It had very similar, if not the same bags you have. They were mounted slightly differently on the top, but the only real difference is that mine were the thickness of your upper plate higher i.e. they had welded a plate flush in the upper spring pocket. The lower end was just bolted through the center of the factory control arm with a large washer on the bottom. With the exception of the bumpstop/steering stop being removed the lower control arm was unmodified. So in essence the top and the bottom of the bags were closer together than yours are when aired out. Giving mine more useable lift. The front bumpstops at that point were the ends of the swaybar. My truck doesn't have dropped spindles on it and it has smaller diameter wheels so when it was sitting on the ends of the swaybar the bags were really compressed. Where yours is hitting the fender wells because of these differences I would venture to say your bags are not as compressed. (Photo #1 is the bag aired out)
In this configuration it took 140 psi to get the truck up to ride height. (Photo #2 is the truck at ride height with 140 psi in the bag. Notice I was only getting about 4 inches of lift))
I fabricated a pair of cups (The ones pictured above 3" if I remember correctly) and after installing them it only took 90 psi to get to ride height. Which was a relief on the poor old air compressor since I was able to adjust the shut off point down from 175 psi to 135 psi. That markedly reduced the run time of the compressor.
All this being said I believe your problem is the bags are too short as installed to get the necessary lift. So your options are, install some cups on the bottom or spacers on the tops of the bags, or replace your current bags with ones that have a greater operating range. I suppose you could also get shorter wheels and tires and stock spindles, but that seems too much like going backwards.
Unfortunately I don't believe there is an simple adjustment or lubrication process to solve the problem. I would go with some cups ( They are inexpensive and effective)) then after installed drive the truck a couple hundred miles and so then you will know if you want to shorten them up a bit to dial things in better.